Once you feel good about tactics, endgame, and openings.... how do you become a strong positional player?

any good books to make the leap... if it's a leap?

Although I hate Silman's personality, his "How to reassess your chess" and "How to reassess your chess workbook" are two fine books to get you a positional foundation.

My System is also a very fundamental book for understanding the concepts of positional play.

Live Edit: I just checked out your profile and saw your rating. You probably should skip the first book of silman and get to the second. And probably should check out Dvoretsky's Strategic Play or Pachman's Modern Chess Strategy instead of My System.