Looks great so far. D sections can be tricky, if you start to get lateral bend. If the limb bends sideways , remove wood from the opposite side of the belly to correct the twist.
I usually put the horn nocks on when the bow is at full brace height and bending about 20-22" on the tillering tree. I do this because by this stage you should have sorted out any potential problems with twist, string alignment and narrowed tips. I prefer tillering to full draw with the nocks on rather than adding them after, as small inconsistencies can change the tiller. These days I use a small taper reamer from Veritas/ Lee valley, to form the tapered hole. Before the reamer I use regular drill bits to remove most of the waste.
