I'm undecided about building both wings at the same time. I actually like to finish one side, then work on the other.
So for now I just put the spar between sawhorses so I can do the baffle/rib work. I want to get the left tank ready to be sealed. For THAT I would like to do both.
Tomorrow I'll tighten up the bolts and match drill the holes. I hae a long drill bit with a stop on it, so I don't damage the spar.