Setting Primary Tension on MKII?

I'm finishing up re-assembly of my bike after gearbox/swing arm work. Doing the primary chain adjustment. As per shop manual, 3/8" (9.5mm) up & down movement....I measure it by watching the top edge of a link when I lift chain then pull it down and measure how far that same top edge has traveled total....but how much force should I need to pull chain up/down as I seem to be able to get the required/more than required amount if I push up, pull down with a fair amount of pressure, unless I've really cranked on the adjusters. Whats the usual....make my finger blue or just lightly lift up/pull down?? This is with the cover still off bike.

I've seen some 45 year veterans show how, put a slight strain on the kick start lever will allow you to see/feel slack on the top run through the inspection hole. Seemed logical. Agreed, the deflection without pressure spec is pretty open ended, but, many things were, assuming fundamental experience.
Yes, too LITTLE slack is destructive. Too much will slap on the case, (witness marks in my inner case)

OK, Thx to LAB's linked thread, I now grasp that no real pressure need for checking chain slack. Will " git-r-done"!

BTW, I did try a few searches on this question prior to posting but alas could not find a thread specifically on how much force to place on chain while checking...LAB must have a magic search clause ;-)