I put two bikes on the rack, but I don't think I could get the roof up at the same time. I also felt they overhung the sides a little too much.
They were just standard "soft-roader" bikes. I would imagine I'd have done better if I'd taken the front wheels off!
The other thing to watch out for is the electric aerial. It's very easy to pack the rear rack, then get in the car, put on the radio and have the aerial try and go through whatever you've packed on the back.