Full disclosure: I am an amateur, not a pro tech (I have spent years fixing other equipment though FWIW) so this is stuff that works for me..pros feel free to add or correct here. I recently got a P90 SG (this will work for humbuckers too) and noticed the pickups were not parallel with the strings. In the past I have resolved this problem in a few ways; in one case when I installed new pickups and rings, the new rings, after I shaped them made the pickups parallel. In another case, I used some foam rubber under one end of the pickup..that was on a P90 that screwed into the body directly. Anyhow, got this 2006 SG Classic, the P90s were not parallel with the strings and when I removed the pick guard I was surprised to find that the P90s were in a frame and not mounted to the body with screws and springs. A new one to me. The frame had arms on both sides with the height adjustment / mounting screws and springs, like you average humbucker mount. So I bent the mounting arms as I have done on a humbucker guitar or two. I would advise to reinstall the screw mounting clips on the frame arms "right side up". The screw makes an outward flare on the bottom side of the clip so if they are up side down the screw will not screw into the clip. You will see what I mean if you look at your clips. So just bend the arms the opposite way of your desired tilt. Here is a good image I found on the LP forum that shows both the bent arm and foam methods: Here's my SG..after bending the arms with a large needle nose, they are more parallel to the strings..the bridge pickup may need a little more of a bend at the next string change. It is already at quite an angle may be all it has..much better then before though.