Hi and welcome.
I am by no means an expert on SGs, but from what I hear they are very middy and pick little buggers. Seem to often not like medium output PUs, prefering low or high (this rule seems to not go for P90s though). Because of the middyness I would immediatly discount the Aftermath. Anyhow, for what you describe the Miracle Man would probably be really nice in the bridge. It is certainly chuggy and since the center and high mids are not emphasized that should play well with an SG IŽd imagine. A lighter and more agressive version would be the Cold Sweat. The Warpig could be another possibility for brutal metal.
Sides that you could also look at the Stockholm P90 if you could deal with the slight single coil hum. That one is proven to work in SGs and really delivers raw agression with fatness, cut, and roar. Amazing one that.
The neck largely depends on the bridge you choose, but if you go humbucker IŽd think the Coldsweat to be a good choice, as it can do both metal and bluesy things. However, decide on the bridge first, then we can talk more neck.