Space is definitely tight. When I did this job, I started with the easiest bolt I could get to first, got it finger tight, then got the 2nd one going. Was not an easy or fast process because the clearance just isn't there.

Adjusting the switch is easy. Chock the wheels if you have it on ramps and set the parking brake. Put it in reverse with the key on (but engine not running!) and turn the switch until the reverse lights come on. Tighten bolts.