Your measurements?

[pooks]

He then successfully measured again using 2 markers----line up a marker on each bone- then lean/sit on a piece of paper. He was pleased
with this measurement.

I'm trying to figure this out ... ? He does what with the markers? (Are you talking felt tip markers?)

If you go to a bike shop and sit on one of their measuring devices, is that the most accurate? I have this image of me putting my well-padded bum down on it and leaving behind nothing but a smooth surface with a ridge where my crack is, sigh.

ETA: When I tried the "sit on a curb" method, I ended up with a piece of paper that was dimpled/pimpled with little indentations where the rough concrete had almost pierced it, in two roundish circles, but no clear definition where the bones were.