I just installed Hotchkis everything on my 69 last month. I went with the BB springs tho.

My car sits dam near perfectly level, approx 1/2" higher in the rear. Picture is in the link in my sig.

My Hotchkis lower control arms came with spacers to go under the rubber isolator (a 1/4" spacer I think) but I did not use them. Good thing I didn't as I would be pissed if my car were level or worse yet lower in the rear. I wanted a rake, even if it was slight.

So in short, yes you can get spacers. But I would also consider the BB springs. You could always flip the SB springs on a Camaro forum for not much of a loss.

Now far as your rear is concerned, I've never seen Hotchkis leafs jack a rear end up that high. You used the provided shackles right?