Choice material suggestion for pivoting arm board

I'm taking on a project this winter which I think will be a whole lot of fun and could very well turn out to be a nice surprise.

Specifically what I'm looking for are suggestions of material for custom pivoting arm boards for a Graham MKI Phantom arm including the beautiful Technics EPA-100.

Be it bronze, high grade steel or a combination of sorts machine shop services are available.

This project will revolve around a Technics SP10 MKII in a custom two arm plinth.
You may wish to converse with the following:
Steve Dobbins/Xact Audio
Albert Porter/Porterhouse Audio
Oswald Mills
I'm sure that I've missed someone...
Each is using different materials for arm boards on "custom" tables.I might also discuss this with Mr Graham himself,probably has some experience in this regard.
Grateful for the info, thank you.