I've gone over a hundred.
I use mantis, dervish, shark, bow, scaredy cat, divinity, bandage, and Fitness.
Always polished. I use some Superchargers, too.
I like to scare the walkers and bow them until they're really slow. The slower they go, the more shots i get before they're in their own attack range, which is unfortunately outside of scare range...
The half the time that Divinity is on, is easy.
The rest of the time, yah, leave one roach alive, so there's no new mobs.