I was thinking that it would vary, depending on which Hulk it is. Savage or Mindless Hulk with the rage ring would be insane, Galaxy or even Universe Breaker insane. However, one of the intelligent (not Joe Fixit) versions, Professor Hulk or even Maestro in particular are already familiar with the Infinity Gems and would definitely be capable of harnessing it's infinite power, Reality Breaker insane.
The question you asked in the OP is which would make him stronger and that would be the red power ring for the reasons LoB stated. what you're saying here would be the inverse, because as the mind stone would help him retain intellect and reason it would work against his rage and reduce his strength
I wasn't implying that it would retain his intellect, I guess I should have explained better. My reasoning is that rage is an emotional response centered in the brain. My reasoning is that an intelligent Hulk would know this and use the Mind Gem to amp his rage.