Who is the least injured, or can take most abuse at the moment. Does that work for ye?
My players find 6 hours to heal to be too Monty Haul
Fantasy does not mean total rejection of realism
Only once should be necessary. My characters learned quickly how to use unexpected tactics to minimize the enemies chance to attack and maximize their own. (gorilla tactics are especially effective against classically trained military, as we USians fornd out in Korea and Vietnam)
I try to inject some realism into my games such as physics when falling and the lovely "dagger through the eye"
gorilla tactics are only effective as the DM allows them to be.
If your group does not like the 6hrs for total healing, thats fine, more power to you guys. I personally don't think it is a bad system (at least not until I read the core books and see if they provide more info).
as for as the monty haul comment I can offer this advise for whoever is the DM. Increase the challenge rating on the encounters. If your level 5 characers are having an easy time killing the kobolds, don't make them minions give them more hp, give them levels in classes (assuming that will be possible, have not read anything about that), or find a CR more close to what the avg party level is. If the players feel that it is too easy, show them how easy it can be by adding more critters.