How would I get more than -2 deg camber with SPC RLCAs?
 

So the SPC RLCAs can net me -2 deg camber at most. Is it possible to get more than -2 deg camber to get something like -2.2 deg camber?

Go to a better alignment shop, sounds like they're being lazy or your car is broken. You shouldn't have any problems going up to as much as -3 degrees.

Unless you mean the part description which states +/-2.0°, that typically means you have 4° of adjustment range from where your car sits on the OEM parts, the factory car is usually around -1.5°-ish so you could have as much as -3.5° or as little as +0.5°

My guess is that you need to install differently included in SPC rear LCAs set eccentric bushings, so that you can get wished camber while still able to dial toe right too. Other similar stamped steel LCAs of such design IIRC don't have that bushing in set. With OEM bushing and at stock height with wished slight toe-in rear my rear camber is -2.4dg.

Are you lowered at all? My rear is at -2.5 with those LCAs, lowered 1 inch.. with even more range if i wanted it.