Plays true with proper tipping, GD shafts have a slightly soft-to-flex wrap due to people not tipping them for std bore.
I did a similar thing with a YS-6 and tipped it like a 3 wood for driver application, although I had a regular flex and wanted it play firm-to-stiff but I'd imagine the theory should be the same. No idea if that's correct but it seemed work out well. I left the shaft an inch long initially to give myself the chance to tip it more if it was still a little soft.
I was thinking of tipping it 1.5" which is 0.5" more than standard and what they recommend for a 3 wood which is exactly what you have done.