hey there, sorry for the late reply. I have bee away over Christmas.
I have currently used 3 walls 40% infill PLA for the mast, printed in 100 mm sections.
I then super glued them together and used filler to fill any cracks and warps and did 4-5 layers of fiberglass with extra strengthening layers around stress areas and joints.
I still havent finished mine but I intend to use two layers of Carbon, one at a 90 degree angle and one at a 45 degree angle for finishing.
hope this helps, David.