You want context before giving me an answer? But I thought this was the internet!
This is a stage race but it's scored on points, I could do well on the other stages, so it's a case of minimizing damage rather than trying not to lose the event completely on the TT.
I've only ever done 2 TTs, both with bike B in TT-ish setup (seat forward, slammed negative stem, clip-ons), and I did OK on them. I will have at least a month to work with any of the bikes.
I have very little experience measuring efforts without a PM, that's probably the variable that worries me the most.