As I posted before I use Fel-Pro head gaskets and have for forty years. I have even reused them many years ago when money was tight and never had a problem.
Until I built my current small block I had never re-torqued a head bolt or stud. At the time of the build there was some internet chatter about re-torquing head bolts/studs. I decided to see if the nuts on my head studs would return to the same location when re-torqued. The heads were installed, after torquing the nuts I painted a witness mark on each nut and the head. The next day, one at a time I broke each nut loose and re-torqued. To my surprise all of them turned at least a quarter turn more and some almost a half turn more.
I don’t think there is any significance to my experiment, but I did find it interesting.