TMP, take your time on Game Types A-C there isn't a whole lot of rush. Just aim the reticule over the body, get a shot and make sure you don't miss for every 5 downed targets. This will force the Salazar target to show up. If you can get a streak going, you can shoot 5 targets...hit the Salazar target in on hit and keep the streak going with additional targets (thus forcing Salazar to show up again rather quickly).
Another thing that I did was try to get headshots with the TMP on the first 5 targets, guaranteeing 100 points per head (500 total) + 500 from salazar for an easy 1000 points.
It gets frustrating though, trust me...it was pissing me off to no end. Trial and error...it happens eventually.
I thought I had something meaningful to put here but I'm at a loss so...booty-butt-cheeks. Oh and thanks to Gackt for the Signature. Because OP Man and Japanese Iron-Man are too beastly.