Steve wrote:

BTW, I have seen some mast extrusion that have a 'dove tail' grove (kind of
a internal track) on the inside that would allow a series of clips to be
used to secure the conduit in place.

That is a feature of Sparcraft/Charleston Spar. Actually 3 little tee
shapes on the inside. One on either side in front and one on the luff
track. You slit a piece of PVC conduit on a table saw, slip the kerf
around a tee and push it in. Pretty neat.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com