I boosted the Treble and Middle a bit but they actually ended up sounding like single coils
On most fenderish-like tonestacks, boosting the treble and mids you'll still have a rather mid-scooped EQ. The "right" way to "push" (well, flatten, really) the mids is to roll down the lows, roll up the trebles, and roll up the volume.
Listening to the Riff Raffs not sure if they will be what I'm looking for? Will they deal with the really high gain?
Yes - but without loosing some the vintage touch, which is a GoodThing(tm) IMHO.
If you want modern hi-gain tones you may want to have a look at the Nailbombs or Warpigs, but from the tone I heard on your vid (sorry but that's about the only indication you gave), I'd too say RiffRaff. I have a pair on a semi-hollow and have no problem using this guitar instead of my SG (Abomb / Mule) for the rather gainy stuff I'm playing with my band.