The post I used as a guide the most was Bucklands post (last link on the first post to this thread. In post #52 of that thread Buckland posted a pdf with the steps to follow and they worked for me. The only thing I screwed up was in drilling one of the holes I hit the lighting wiring and one of my exterior lights no longer works, so be extra careful about drilling out the back - I thought I was but alas....
He installed the top ball for the struts first and the found the location of the bottom.
Anyway, the pertinent text from Bucklands text for your questions may be:
Step ten: lower the roof. I made a jig from a ¼” thick piece of wood 1” wide and 42” long to layout the lower strut locations. drill a ⅛” hole about ½” from one end and then measure, on center, 40” and make a mark. Drill 7/16” hole. It should be 40” center to center. Hang this on the upper ball bracket and let it hang down then move it towards the center of camper. We are looking to put this mark 2 ½” up from the bottom edge of the front overhang. Do this to both sides and really take the time to be sure you are spot on! Then make a divot where you are to drill.
It looks like the document might be at this link: