Was able to get back to this today and with the LOP marked in I could use this jig I made to set the minus 2 degrees of pitch and scribe in the curve needed for the steel butt plate.
with that cut I could mark a centerline and then the 3/16 of cast that was asked for.
After the beak of the plate was set in and with the smoker to in use I could get the plate settled into place.
then marking a centerline from the socket to the buttplate I could zero in on where the ebony grip cap needed to go. I had made a few grip caps up at one time so it was handy being able to get one from the drawer for this.
So with that pinned and epoxied it will sit in the clamp overnight with the next stage being some shaping