For all the talk this season about conference imbalance in the NBA and the inequity of its playoff structure, things seemed to have worked out just fine. Measured by point differential, we’ve ended up with the best teams from the Eastern and Western Conferences in the finals, and fans everywhere get the chance to watch a rarity in pro basketball: an NBA Finals rematch.Who’s going to win? The old adage is that defense wins championships, but this matchup is all about the offenses.The San Antonio Spurs and the Miami Heat have had the two best offenses in these playoffs and, surprisingly, both have been more efficient than they were in the regular season. Their offensive systems are different, but they have the same basic goal: Create good shots. With that in mind, here are some things to watch for:Spurs movementIn April, a study by two members of the Harvard Sports Analysis Collective found that, after controlling for time of possession, the Spurs’ offense had more movement and more passing than any other offense in the league, and by a wide margin. Indeed, according to the NBA’s SportVU Player Tracking Statistics, the Spurs’ offense has featured more movement during the playoffs than the other three conference finalists.Movement Per Minute of PossessionPassing and ball movement are not perfect proxies for offensive effectiveness, but in the Spurs’ case, they are symptomatic of an offense that is working well. San Antonio doesn’t have any player as individually brilliant as Miami’s LeBron James to consistently pull good shots out of thin air, so the Spurs rely on their collaborative system. The distance traveled is of particular importance. On average, the five players on the floor for the Spurs cumulatively travel nearly 500 feet farther per minute of possession than the players for the Heat. That’s 500 extra feet of screening, rolling and cutting, searching for seams in the defense and open space on the perimeter.The Heat’s defense plays at a frenetic pace, aggressively trapping pick-and-roll ball-handlers and flying around the perimeter in a series of rotations to cover shooters. It can be devastating when done well, but the Spurs are uniquely suited to turn this aggression against the Heat.Shot selectionWhile a key indicator of the Spurs’ offensive health is the movement and passing they use to create shots, the key for the Heat is simply the location of their shots.The Heat spent most of the past two weeks burying the Pacers with 3-pointers. These outside shots buoy Miami’s offensive efficiency, but the Heat’s 3-point shooting is also a reflection of how easily James, Dwyane Wade and the Heat’s other ball-handlers get into the lane and collapse the opponent’s defense.In his NBA Finals’ preview at Grantland, Zach Lowe pointed out some of the methods the Spurs used to defend the Heat in last year’s playoffs, and how they resulted in a slew of mid-range jump shots. If we look at the breakdown of the Heat’s true shot attempts (which includes field goal attempts and trips to the free-throw line) we can see just how far last year’s pattern was from what the Heat have just done.Miami Heat Shot SelectionFor the Heat, 3-point attempts are tied to their ability to get inside the defense. James, Wade, Norris Cole and Mario Chalmers were able to get into the lane with ease against the Pacers in the Eastern Conference finals, and the result was that nearly 30 percent of Miami’s true shot attempts in that series were 3-pointers (which they made at an obscene 40.8 percent clip).In last year’s finals, however, by walling off the paint and offering up mid-range jump shots to the Heat, the Spurs were able to keep them away from the rim, off the free-throw line and inside the 3-point line. The Heat will surely have some adjustments ready this year, and we should be able to tell a lot about how they are working just by looking at the locations of their shots.LineupsThe offensive systems each team employs to create good shots revolve around lineups. The Heat would prefer to play small, arraying three and sometimes four shooters around James. The Pacers were loathe to change gears and try to match up with them, but the Spurs may be more willing. They have more depth than any of the teams the Heat have played in these playoffs, and San Antonio is much more comfortable using that depth in a variety of arrangements.A big issue in last season’s finals’ matchup was the way the Heat’s small lineups forced the Spurs to separate Tiago Splitter and Tim Duncan. The Spurs used that pairing for about 20 percent of their regular-season minutes, then just over 11 percent in the finals. But Spurs’ coach Gregg Popovich has been more aggressive this season about experimenting with different lineups.It is tricky to parse statistics for the Spurs between big and small lineups because of the big and small skill set of Boris Diaw. When he’s playing power forward for the Spurs, the “big” or “small” nature of the lineup depends on the matchups and what he’s being asked to do. But having him on the floor allows the Spurs to have their cake and eat it, too.Back to the NBA’s SportVU Player Tracking Statistics: Diaw was third on the team in touches per game, at 49.2, during the regular season. While Diaw is capable of scoring in a variety of ways, he averaged just 9.1 points per game because his role in the Spurs’ offense often called for him to be a facilitator. He averaged 38.9 passes per game; about 79 percent of his touches involved moving the ball to another player. This usually worked out well for the Spurs, as Diaw is among the best big man passers in the game. His assists created an additional 6.7 points per game for the Spurs during the regular season.In the Spurs’ Game 6 victory to close out the Oklahoma City Thunder, Diaw saw a lot of extra touches by virtue of playing some extra minutes, but it was what he did with those touches that made the difference.The Boris Diaw StoryIn Game 6, Diaw’s touches accumulated nearly 50 percent more points for the Spurs than they did during the regular season or in the series to this point. This increased output from Diaw was needed, with the Spurs struggling to hit 3-pointers and Tony Parker sitting out the second half with an ankle injury.Diaw’s ability to shift between big and small defensive assignments, and scoring and facilitating roles on offense, may allow the Spurs to sidestep a lot of the matchup land mines the Heat have waiting for them.MarginsThese teams are incredibly talented, well-coached and, ultimately, evenly matched. Each has a series of counters available for every obvious advantage the other will try to exploit. That’s why this series will be won at the margins and in the minutiae. Little things — the Spurs forcing the Heat to make one extra defensive rotation, the Heat getting the ball to a 3-point shooter instead of settling for a seemingly open jump shot around the free-throw line, and the tiny in-game matchups that shift the rotations — will be the deciding battles.