You bring some exc. points here as well, and the methods of construction you cite are well-known, and well-documented. The use of, and the top of the natural outcropping being just below the Q's Chamber does make sense, and the larger the outcropping is, the more work they saved.
A downhill ramp....interesting thought, probably the first it's been proposed here. Also it does makes sense, assuming they did have an efficient method of raising the blocks thereafter. (You mentioned the 35th course, and there are other courses that are much larger then those above and below....I've studied Petrie's chart on this till the cows come home, w/ little, [no] progress, and maybe the blocks of these larger courses were only dragged up the ramp, and then placed, i.e. not lifted at all, [on successively higher ramps].)
Thanks for the common-sense approach, but wasted effort on most here.
Campbell's Chamber roof blocks are Tura Limestone until proven otherwise.
THE Cartouche in Campbell's Chamber IS Authentic, as are ALL other RC's Glyphs, until proven otherwise.
"This Forgery 'theory' has more holes than a sieve basket."