Resident Evil 4 -- Mercenaries mode?

Okay, So I'm going for a handcannon, but I need a little help. I've already 5-starred all the stages for Ada, Krauser, and Wesker. (But that's only because they're awesome, and have nice gear!) So I'm stuck on Leon and Hunk. I admit that Hunk is better than Leon, I'm sorry to say that Leon SUCKS in the Mercenaries mode! Any tips? Another hard thing about those two is when the boss comes, (especially super salvador and the bella sisters -.-) There's no "fast" way to take them out, such as Krauser's arm, and I get scared and end up avoiding the boss lol. Help would be appreciated! Thanks lol!