I used a piece of .090 in. thick aluminum sheet metal 40 years ago and it still works fine.
It doesn't absorb water, doesn't squeak and doesn't rot away. metal from an old STOP sign would work nicely as that aluminum is made to resist corrosion. You can't even see it.
Car is 40 Ford.
If you are wanting to use the webbed type pads do not put grease on them. Ford used a spring lubricant. A modern option is SlipPlate.