I wouldn't think he's too ut unless he's starting to give you some ridiculous EW's.
This is one of the main reasons I put D in her own room and left J and E together. Two of them together is such a challenge to be able to 'switch off'. But it does get easier. At one point, I removed the knobs from the dresser drawers, and absolutely everything from their rooms aside from bed, mattress, blankets and nightlight. And even that was used as a missile sometimes in the middle of the night
When they're toddlers, you can sit in the room and simply keep putting them back in their bed without saying anything and after a few olympic nights of doing it they figure it out. When they're around 4.5 years, you can have a discussion about it. In between it pretty tough. We had some pretty rough nights with the girls in the middle years. Even E still needs me to sit with her and make sure she doesn't get up. She's getting better but she's still trying. And she's an angel.
Do they bath at night? I remember reading that for spiriteds the bath can wind them up and we certainly found that when the girls were younger. Now if we do baths at night we make sure hair is dry before they go to sleep. Otherwise their temperature has dropped too much and it stimulates them. Baths/showers during the day work much better.
I think I would keep with the earlier bedtime so they're not ot/os before you even get in there. It also gets YOU in there before you're getting frazzled and dreading another bedtime.
Just out of curiousity though, what would happen if they were left to their own devices though? ie no parent involvement unless things were going crazy in there? Would they eventually get bored and go to sleep? I have a friend that did this with her spirited and swears by it. But that was one kid in one room. I don't know if I'm brave enough to try it with two :/