Thanks for the posts! I agree, the solids crashing out in the fridge are mostly the TBAF salt. I don't cool it below zero though. My theory is that if you freeze out the water then the TBAF decomposes (it is actually required to stabilize the TBAF... I have a reference if anyone wants it). When I set it on my bench to warm up for ~1 hour the solids never fully redissolve so I'm sure we're working with less than 1M concentration. And using excess kills my reaction.
So I'd really like to find a way to titrate for the F- concentration in an organic solvent. I was thinking of bis-silylating something that when exposed to 2 eq of F- would generate a dianion (similar to titrating your LDA or nBuLi). But the water in the TBAF would complicate the equilibrium.