I don't know anything about the chasing riders but this section should be ideal for Hippy - relatively heavy but very powerful. I was hoping he might build up a bit of a buffer as he is less at home in the hills which will come tomorrow.
The lead looks like about 12-15 km or around half an hour. Was definitely longer earlier in the day. Stops will have more of an influence on it than riding speed. Hippy is an out and out racer so I would expect him to push hard tonight, sleep only when tired and eat on the go. I'm not sure how well-rested he is but, if he is, with 600km to go, he might ride through tonight, looking to finish tomorrow night. If his chasers do the same, it will be a tiring day for them all.
Edit - the tracking is far inferior to other races but I think that it shows that Hippy had a shorter rest last night than his two nearest chasers, therefore they have ridden faster over the day and should be better rested. Based purely on that, I think the guy in second is probably the favourite. But Hippy will put up a good fight and be determined to win it. If he sees another rider pass him, he might just find another gear.