Here is my set-up. VHS on top of the main on the stbd side. Wind
instruments elevated and forward; windex elevated and aft; lightening arrestor on port; aquasignal tower center. I have since added a BIBI LED windex light tothe base of the Windex stalk. I would keep the mass low (aluminum or heavy fiberglass)
I also have a split on top of the mizzen and two more VHF
antennas. This is a 1" SS pipe. The center strut was intended for a Shakespear TV antenna (removed) YOu also see the Mizzen Windex mounted on a Fiberglass
U-Channel cantelevered to stbd. Also added later is a BIBI WIndex light.
We have a primary VHS on the main; secondary VHS in an aft cockpit
locker using an antenna on the mizzen; AIS
uses the second mizzen antenna. I like the suggestion of mounting on a spreader as long as there is no chance of mucking up a sail.
The SS mounts all demonstrated corrosion
and I had to up-size the screws on the re-fit and paint
job. Lots of goop in the threads now. I recommend not mixing your metals. You can get pultruded fiberglass
shapes from McMaster-Carr as well as aluminum