Right or wrong, but done
For what it’s worth. The holes were already reamed and dimensionally verified. I had already made drift pins (long taper and very even/smooth before you ask). Even with no perceivable/measurable hole misalignment, lubed shanks, etc. I still couldn’t get more than one bolt/pin in. I tried persuading such with a rubber mallet. The structure laughed at me before calling me names.
The center section, and spar caps for that matter, are quite flexible without the layers fastened together. Tightly clamping would have probably been beneficial if I’d continued with the mallet. An air hammer/rivet gun with a fairly low pressure setting provided enough impulse to install the pins and bolts. Yes, there’s some burnishing. The cad layer was basically removed from the bolts. I don’t foresee the high shear bolts going in with finger pressure. Maybe this will help somebody down the road.