That Wheeldock looks great. Does it move when you ride it in? When you release it is it secure until you can get on the bike?
No problem with either pulling in or pulling out. My garage floor is level, so I leave it in neutral, but in gear is fine.
When riding in, just approach slowly, get bike straight in, then ease forward until most of the way in--kick the release lever, and the chock closes on the (back of) the front wheel. This eases the bike all the way in, without moving the chock, and holds bike securely upright. It also prevents bike from rolling forward or backward. I then put down the kickstand just for the extra security (although I find it's not really necessary, and KS doesn't even touch ground; chock keeps bike upright and is very stable).
When I'm ready to leave, I hold the handlebar
just for extra security, step on the chock's holding bar to release it (to allow rearward motion of bike, although it's still held upright by chock
and kickstand), then mount up and put KS up. Again, these precautions are for extra security, but not really needed...WheelDock is very stable.
If you want to provide extra resistance to "sliding" of chock, a piece of rubber mat under the main support can help.