Thibodeau, asked about the club’s issues in defending the arc, said he generally focuses more on making sure his group limits attempts rather than the opponents’ 3-point percentage. (For the season, the Knicks have allowed the fifth-fewest 3-point tries in the league.) But a plain look at the numbers against the primary contenders — 53% of Boston’s shots against the Knicks this season have been from deep, while Cleveland checks in at 42% — would suggest New York has plenty of schematic work to do against the cream of the crop.