Oh my, this should be interesting. For the main match, I would say that Gogeta should be able to destroy Bills with mid-difficulty. However, nobody can accurately judge the second round because Whis has no feats besides teleporting across the galaxy with Bills, which Goku could do with Instant Transmission. For all we know, Whis could peel his face off in the next movie to revel himself to be Hulk Hogan in disguise, and the rest of the film would be Goku and Hogan battling in a steel cage match.
@othus12: So Whis would be around 1.5 times as strong as Bills with that logic then. And for the knockout hit, I don't exactly consider that to be an amazing feat, since Bills was already exhausted from his fight with Goku, and didn't even have enough energy to destroy the planet. One could argue that he could use that extra 30% he had in store, but I digress. Whis appears to be more than a simple brawler like Bills, so I wouldn't doubt it if Toriyama gave him a hax ability to compliment his fighting powers, particularly an ability that uses his staff to some degree.
I am just going to have to say "not enough information" for now.
I think an admin needs to delete the Whis part because he's a featless character and therefore unscaleable.
Also Bills probably crushes SSJ4 Gogeta because Bills speed is too high. Bills speed was on par with Goku spamming Instant Transmission. He's so fast that he can keep up with teleportation. SSJ4 Gogeta brute strength would probably far outclass Bills to the point that Bills can't even touch him, but all Bills has to do is run away for 10 minutes and Gogeta defeats himself.
Depends on how Gogeta goes about this, if he dicks around and wastes his time then Bills could potentially hold out, though he is probably too arrogant to run away. If Gogeta decides to be serious then he'll probably beat Bills with around the same amount of effort as Whis would.