A present vote by Flake in committee would likely mean a tie vote and it comes out of committee with no recommendation. If he votes present in the full Senate, I don’t know what it means - tie vote with Pence breaking a tie if no one else defects?
If he voted “present” on the senate floor, it would be 50-49-1 if all of the RATs held. Pence wouldn’t need to break the tie.
I still suspect that Manchin has to vote yes on the floor, lest he commit harakiri in his Senate race.
That would make it 51-48-1.
It would depend on Collins and Murkowski in this scenario.