[Prophet Tenebrae]

3. What should the relationship between the two halves of the persona be?

This is an aspect that I've seen explored a few times in really interesting ways but tends to be overlooked in favour of clothes bursting smexy...

I suppose - again - it's pretty much the case that the quintessential version of the Hulk is like that... Hulk hate puny Banner and that's about the size of the relationship.

And of course, if it's more of a standard She-Hulk type lowered inhibitions thing then there's no real divide.

Personally, I think it's always kind of missing a trick. Interaction between the two (or more) personalities always seems like a good source of tension... especially if you have a situation where the hulk persona is trying to provoke the protagonist into transforming and allowing them control.