I might be misunderstanding, I've read it mentioned before though, you're cutting channels in the positive post insulator? How does it not short?To mod my Tobh...
I unscrewed the 510 pin, stuck a micro screwdriver through the center post hole and twisted and tugged until it came out. There are two delrin insulators in mine. I pulled them out and used flush cut wire cutters and a carpenter's knife to carefully clip a 2 mm channel top to bottom through both insulators. Put it all back together and make sure the channels line up. Works like a charm and better than I thought it would!