We have a full wall and I think a little logic is what I employ on this one. First off, I am surprised (knock on wood) at how nice the thing goes in and out. Never an issue, quick, and I can see the length of the coach and can see if something is in the way.
I think if the spot is fairly level, then I will put the slide out and then level. If it is quite unlevel, especially leaning toward the slide side, then I will level first and then put the slide out.
I like the room that the full wall gives to the coach. It is cavernous.
WW