Thanks, that's pretty much what I figured. It makes sense to me that turning the engine backwards runs a risk because of the timing chain (or timing belt on other engines), but since I already know my timing is already wrong, it seems less of a risk!
As for following the procedure, I faithfully followed the one I had.. however....
Since this is my first one, rather than my 40th, I figured I'd learn something. I would rather it had not been the hard way!
I'll do a couple of measurements this weekend, but I think I'm going to remove the engine to finish the job. It's just too tight to do much in there with the engine in place.