Just a quick comment on the thickness gauge.
If you have any welding skills or acces to a welder, they are so easy to make and make strong so they don't flex. I picked up a dial indicator at Harbor Freight for around 15 bucks and your in business.
I use mine with confidence , it certainly beats guessing.

Tom

How'd you build it (Ahem... With pictures if ya got em':whistle:)?