Three helpful hints:
A) keep your barrier on at all times
B) Buy the Epoxy Mod for your bombs to freeze the clones in place
C) level up your laser tracer and your shock rocket, because they'll do the most damage reliably
And it was with these tips that I was able to get past the clusterfuck of clones and reach the final boss. Thank you.
But yeah, I was able to finally finish Ratchet & Clank: Size Matters today (that last boss was a real bastard, though). Not sure what to play next. Maybe either Dark Cloud 2, or maybe get a little further in Final Fantasy (PSP version).