I also use Verniers to adjust mine, probably the same method as yourself measuring from the end of the swingarm to the bolt 'stop' using the depth measure.
My chain is still within the service limits after 31,000 miles, so I guess the chain must be running true using the vernier method (I've never trusted the marks on the swingarm, although they do look roughly at the same wear mark) I changed the front sprocket at 15,000ish which seems to have helped the chain stay in good nick. But, I'll probably replace the lot before the summer for no good reason other than I don't want to tempt fate (my original chain lasted 28,000 miles).