Tony,
Look into using MDF for your tube bending "forms". shapes easily, and at the thickness you need to grip the tube (1.5") plenty strong. plus you can glue 2 sheets of 3/4" and get your form easily.
I would worry too too much about the compass. My compass is right on my binacle, with all my instruments surrounding it on the old-fashion Edson pods. plus the wheel, along with all it's internals (chain, brakes, screws) that sometimes have ferrous materials. Your nav instruments can't be too bad screwing with the compass. if they are, just get your navman repeater to spit out GPS heading. Close enough for most uses!
-Keith
-m
-km
aka, "sell out"
S/V Beyond the Sea
C&C 35 mkIII