As a one time owner of a Hamer Slammer (Double humbucker strat style with floyd rose - mine was crap).... if you think the tone on your SG is poor in comparison, you should send it back, you must have a bad one!

I find SGs neck heavy, but when I used one I found it easier to play sitting down if I had it across my left leg rather than my right... You might also want to think about putting a couple of books or something under your left foot (if your guitar is on your left leg), or sitting in a lower chair if it's sliding away from you.

If the tone is pants, get rid of it, if it's the physical aspect, you can work with it.... It's easier to rock out standing up, maybe just do that... :D