In a game i'm playing the party is about to fight a relatively high level cleric exact level unknown but as a rough estimate i'm guessing 10. The plan seems to be since we have a modest chance of catching her off guard, of grappling her and then pounding on her while either the barbarian grapples her.

The question is what kind of hour per level buffs are available by lets go worse case scenario level 6 spells or swift or immediate action spells that could end the plan before it starts.

Now the party's not super optimized so i don't expect the villain to be using night sticks or any similar tricks