I to have a PitBull lift. It does the job but it has a weeknees that you are sure to come up against in your particular situation. Even when using the lift on concrete I sometimes find the lift rubbing against the floor and have to force it to turn, sometimes it just won't budge. The problem with the lift is the wheels are very close to the frame assembly, which I suspect adds to the stability. In one of my discussions with PitBull they advised shimming the wheels to create some space as not all concrete floors are perfectly level, so they are aware of this issue. I like my lift and it does what it is supposed to do but I would recommend a lift that has more space since you are sure to not have a level surface. I can guarantee you will be cursing when the frame is stuck against a less than perfect floor. Just look at the photo with the bike already strapped and the clearance you have, that would be my choice. Just my thoughts.
Ray G.