Your absolutely right Frank, and of course you can measure and make a judgement call but is it really worth it, given the work and risk? Also there is something else, Toyota do say you can measure them, followed by........if some twist or break you should replace them. Did Toyota base those calculations based on an engine that the bolts had gone through thousands of hot/cold cycles on a 30 plus year old engine? Of course not, they based it on current knowledge at the time, the huge number of big end failures prove my point.
What if when the head gasket was done and the old bolts were reused, if so have they become loose? If not loose why has the gasket failed again? Then the part about over oiling the threads absolutely correct again, if the bolts have come loose oil will undoubtedly have worked it's way down the threads and pooled below the bolts this brings back another 'what if' of the possibility of hydraulic damage, perhaps the person who did the gasket was a carpenter?
Perhaps my work ethic as a mechanic is a little strict, but I am good with that.
Regards
Dave