Rhino worked for my ss ok (are your cars lower?). I actually had the rear up on wood too - drove up at same time. Pretty easy... took a couple tries - sort of have to commit when going up! I recommend a spotter
If your front ramps are sliding, put a rubber mat or thin carpet remnant under the ramps. I attached a piece of rubber floor treads under my wooden ones so they didnt slip - you can just see the little rubber strips in front of the wood ramps.
BTW, check your rhino ramps for stress cracks occasionally (I'm on my second set). I still use jack stands loosely placed under the frame rails in case they fail. A guy at my work had a lift failure and it messed him up pretty bad getting crushed! I dont take any risks under my car - horrible way to die.