Pulling them apart gets easier with age - in fact, they may loosen up enough that you'll want to run them through the dishwasher to tighten them back up. Getting them on straight just comes with practice.
For all the excess material, I do 2 things - I double up the thickness under the clamps (hard to do when your Snaps are new, but will also stretch them out a bit) and I also use those hair clips and gather up the excess & clip it around the frame; I could have 4-6 on my bigger frames at any given time:
I also use fairly large QSnaps almost all the time - the 11x17 is my main go-to size, but I do have the smaller 8x8 (I think) and 11x11 for my travel projects. Much smaller than that, and I revert back to hoops if necessary, just for very small pieces (like ornaments that will fit entirely inside).
I do sometimes borrow an extra hand on the big ones (I will often extend the 17s by 3 or 6") and have DH hold my fabric on the corners so I can get the clamp on the first side; after that, I can usually get the other 3 by myself...
I don't think I have any pictures of one of mine all clipped up - I usually crop my update photos to not show the workings The main thing is to just remember, as with any new tool, it takes a bit to get the hang of it; QSnaps are no different - and once I got them figured out, they really are all I care to use these days, though I do still have scroll frames for my big SQ & Chatelaines.... Good luck!