I finished cutting the spacers and loosely fitted the aft deck.
It took awhile to get the fuselage level fore and aft and across the longerons. Once done, I strapped it down with all the shims in place.
The aft deck was not level after getting the forward level and strapped down. A little manual manipulation of the aft fuselage got it level in both directions. I clamped it all down and started drilling.