My shop was level enough I was able to level the plane just adjusting tire pressure so no problem there. You donít mention it in your post (and are probably aware of this already) but without the engine on you will need to support the 1st wing after installing it so the plane does not tip to that side. With the engine mounted that is not a concern.
Regarding installing with the control tubes in the wings, you might be able to get away with it but I wouldnít and didnít. I had to drive the lower bolts with a rivet gun to get them in (after putting them in the freezer overnight and lubing them up). I donít see an upside to installing the wings with the control tubes attached unless you already have the wingtips on and used rivets rather than screws to attach them. However, youíll have to remove the wings at least once before final install so you could always trial fit the wings with the tubes attached. You shouldnít have a problem getting the drift pins in the wings and fuselage spar. Then you could see for yourself whether you have enough room to drive the close tolerance bolts in.
Beaverton Oregon | RV-8A, Very slow QB
No Pithy quote here; just the sincere hope that your day ends better then it began