915D2 driver

I push balls right after getting my D2 and making adjustments to a heavy draw setting I'm nailing balls straight down the middle of the fairway.

In my opinion with your driver swing speed regular flex sounds fine. Regular flex shaft should work, a stiff flex shaft soft stepped could work even a Stiff flex shaft may work. It all depends on your swing, swing speed and what feels best/most comfortable for you. When I got my clubs I thought I would go with Regular flex and steel but in the end I went with Stiff flex, graphite and soft stepped once on my irons. Normal Stiff flex graphite in my Driver, 3 Wood, Hybrids and normal stiff flex steel in my Wedges. My swing speed is around 100 with my driver and around 90 with my irons.