Stage 19 is only like 65 miles, and the cut off times depend on how fast the winner goes I think. Is it the faster the average speed, the smaller the cut off? And they do it in percentages.
So if they do a 10% cut off for stage 19, and they do the stage in ~3 hours, it’s an 18 minute cut off. Assuming Cav catches up with everyone else on the galibier descent, and starts d’huez with them, and Andy (yeah, Andy..) climbs it in 45 mins, Cav has to do it in at most 1 hour 3 mins, which isn’t massively quick, but it’s not slow.
I don’t know if those numbers hold up though, I might be talking rubbish.
And galibier is a massive climb, I think Cav will struggle on it. It’s just that it’s got like a 45km descent afterwards, so I think he should be able to catch others.