Thank you for the kind replys regarding my setup.
My first thoughts on the mast were to use a steel / aluminum mast for strength, but seeing how bad the storms can be here in Canada due to the great lakes effect I decided that safety was more important then the strength issue. After all plastics nowadays are as strong as metals, it's how you use them effects their usefulness.
So, PVC pipe was born, first attempts were without the guy ropes, big mistake, too much flex / whip and eventually the whole setup came crashing down on the roof. If it fell the opposite direction the neighbors car would of got the impact, good job I'm insured, more about insurance later. I used two sets of steel ropes to stop 90% of the whip effect, you cannot take out all the whip, you must leave some movement, otherwise you'll end up with the same effect as with no ropes. Think of the mast as a tree, the roots of the tree are the guy ropes, if their strong enough and enough of them then no problems, unless its a hurricane, then you know the answer already !
As to the lightning aspect, well plastic is a good isolator, but.......plastic, especially moving parts can generate a lot of static electricity, so you have to weigh up the pros and cons. You cannot rely on plastic pipe being your sole mate as far as being safe, you still have to consider some form of getting the static away from the instruments, hence the basic neon lamp discharge setup, all connected to the house earth. I"ve had no problems since with storms or static, so something must be right.
As far as steel pipe coated in plastic tube, well, you may have to try it, but I'm thinking, all that steel pipe is still asking for trouble regardless of the plastic jacket offered by the pvc pipe. I'm sure others will have their own views on all this, sometimes its a matter of trial and error, in my case I was hard hit, but the recovery was sweet, meaning no more issues, but that can't always be the case with every setup. All setups are unique, what works with one won't always work with another.
Last word about insurance, how many of you have a separate policy for their weather equipment, my advice is unless you have spent more then $2000 on your setup don't bother with a separate policy, including the mast falling down. My insurance told me just claim on the main house policy, you'll be covered, but again worth checking......a fallen mast from the roof can cause more damage then what its worth ! CHECK FIRST. I was lucky.