I'm about to undertake the rebuild of a Weber Duo-Art stack. I want to
make sure that the valves will be as good as possible.

I'd like to know how to choose the correct type of leather for use in
valves.  Which type of leather?  What about the nap?  How do I know that
the leather I've chosen will give me the best valves?

Similarly, if I want to rebuild the pump using leather, what is the best
leather for that?

Many thanks in advance for your advice.

Eli