Shai
This has always been the question for PvE classes. Ask some Sanctorum members as they have devoted mostly their time on Monster Clash. But based from on my experience, if you are doing boss hunt or Colosseum, just have PvE on your accessory/cloak/mask. Why you might ask? It's because for some reason, bosses--and colo boss--has a low amount of defense compared to monsters at Monster Clash. That is why if you have full PvE on your gears (fashion included) you will often see your damage amounts to '1' i.e. you reached the damage cap. However, using full PvE on Monster Clash somehow bypass the limit. It is probably because Mazey increased the defense of Monster Clash monsters and increasing/removing the damage cap as well. I could of sworn that I saw a patch note stating that.
I might not be able to give you the values or even the fact that the defense as well as the cap was altered for monsters but I assure you that HP had been. I am basing this mostly from my experience with having a full PvE and trying it out.
Off Topic: If this is a necro post, I apologize. I'm bored and just decided to check Forums again.