After the fixes were done I could prime and assemble the left main spar.
The doublers and extension pieces were primed separately:
Assembled back the extension piece:
Assembled the doublers with the AN173 bolts, torqued to 37 inch/lbs in a pattern I found in a Cirrus manual:
And some witness marks on the nuts:
I initially torqued the bolts in the right wing to the standard value of 25 inch/lbs and added 4 inch/lbs for the friction of the nyloc. This felt really loose and the nut could easily rotate together with the bolt. After checking another time with TAF I found out that TAF torqued these to 37 inch/lbs. This is more than 29 but still less than 40 inch/lbs (which is the maximum according AC43 13-1B). And, as I learned from the clamping force test is that adding layers reduces the clamping force. So a higher torque value cannot hurt here.
Next I have to re-torque and add new witness marks to the bolts of the right spar.