I believe he will start in a good shape, otherwise they wouldn't be confident on going to the Tour with him. If he is staying one month in Tignes, they believe he will finish the training camp in good shape.
I'm almost sure regarding two things:
1) They desperately want Vingo to participate in the Tour, especially given their season so far.
2) They don't want him to lose his aura i.e. the Tour victory will be the goal, not just riding it to prepare for the Vuelta for example.
And those two goals may actually be conflicting if Vingo can't reach good enough level. IMO it's not possible that the shortened preparation won't affect his form, their best hope is Pogacar strongly feeling the Giro effects at some point (maybe that's why they are considering the Tour in the first place).