The bright side of being a cover driver, is that the time goes towards your progression when you become full time. So you won't wait the 3 years (now going to be FOUR, 4 years on the new contract).
Not sure how much that's going to change with the new contract, but I had NO problem becoming a cover driver while waiting to go full time.
Now I'm a swing (read: unassigned driver, no route) full timer, and love it. I get to see the world! lol