re: Fibonacci Gauges

I like you tip inserts JJ...

To me, pop rivets sound scary (without the snap & crackle) for establishing correct pressure... be an issue if it was Lautrec... never considered them when I made mine... nor did I know about Chicago screws.
I opted to make mine out of (surprise) 2 laminations of 3mm MDF.  Each of the layers permitted me to recess both the countersink bolt head and the nut to permit pressure (re-)tweaking,

I used a wingnut on one of the fastener sets to lock it down... hate loosing settings between operations.