I'm pretty sure I know the answer, but I'll ask anyway. A thumb mold cannot be made into either a Vise IT or a Turbo Switch Grip compatible slug right? You basically would have to get one of their slugs and attempt to drill/shape/carve it to try to duplicate your current "perfect" thumbhole. I'm entertaining the possibility of moving over to Vise IT, but the amount of tweaking I've done to my goto ball thumbhole would be very hard (in my opinion) to duplicate. Hence the question.