Setting gridz to 0 (or anything less than zero) will only generate the base pattern. This is useful in cases where you want to use those wonderful printable holes on other models.
Old version of cutters had many shared surfaces which caused lag in preview window and caused fast-csg fail to provide speed boosts. Replaced with minkowski function to get the fillets. Benchmark: 5x3x6-5x2 reduced from 8 minutes to 6 seconds. Fixed a small error with the outer size (42mm to 41.5mm) to account for tolerances. Created gifs to illustrate the scripts functions.