1) I want to see them both die, but Sentry more than Hulk, so I say Hulk should win.
2) Sentry tries to calm Hulk with his stupid glow but it fails and Hulk hands him his butt after taking everything he's dishing out, but, all the solar radiation from Sentry's attacks wash out the gamma radiation (yeah, I know) and after the fight Hulk loses his Hulkitude.
3) Hulk prolly, it's his book and his event. However, Sentry could win to start backing up his hype.
4) Hulk is a Skrull or She-Hulk beats him. I'm foolin, kinda.