JakeTheBank
Return of the King
Yeah, I've read a lot about Sentry and Galactus, too.
And really, outside of his hyperbolic statements of possessing the power of a "million exploding suns", nothing he did ever suggests that he could stalemate Galactus under his own power. It was a random off-hand statement made by Spider-Man and later confirmed by X-Man.
To that end, we don't know the context of that fight, and if you knew enough about Galactus, you'd know that depending on his hunger levels or any other forms of plot devices or weapons, "stalemating" him suddenly doesn't sound as impressive. You could argue Thor stalemated (if not actually scored a technical victory) over Galactus via the Godblast years ago. You could argue that Reed has stalemated or defeated Galactus via the Ultimate Nullifier.
Using off-panel events/statements as "proof" for Sentry or Void's superiority doesn't do him any credit. In fact, the only feat of his that comes close to possibly giving him credit in stalemating Galactus is when Void overpowered Molecule Man, who was a far, far, far cry from his optimal levels.