Yeah, the Hellslinger is a weird, weird mech. I pulled the missiles, since the stack on the left shoulder just makes way too easy a target for anyone shooting at it.
I made the following build prior to the quirks and it worked surprisingly well. Came up with it almost as a joke after a frustrating couple weeks of builds that underperformed:
HELLSLINGER
2ERLL in the shoulders, 2LPL in the arms, 2 Flamers that I originally threw in as a joke, but are surprisingly effective in brawling because of their blinding feature.
This doesn't take advantage of the quirks, however. If I were building this thing for CW, I'd build it a lot differently, but for solo PUG drops, that one's pretty fun.
For CW or something that's a bit more viable (competitive rather than fun), I'd still dump the shoot-me!-missile-rack and go for something like this:
HELLSLINGER
4PPCs in the high-mounted shoulders, enough heatsinks to chainfire them for a sequence, and a couple MLs for backup. Obviously you wouldn't be brawling in it and yeah: it'll run REAL hot.