PCV MAST
I have a A99 antenna up on a 10 ft 1 1/2 pcv pipe . I mounted it on side of a flat roof garage with bottom of antenna extended 3 foot above garage roof, I used 8 inch stand offs two each, I may put a 3rd one .
But so far seems to be ok,, haven't gotten big winds yet but not to worried as antenna don't have much drag surface, I have seen many stand the elements for years, , I research everything as former Government Quality specialist and 30 years in Naval Aviation , and have experience in wind and drag .
However I wouldn't go smaller than 1 1/2 di and wouldn't go over 3 ft above stand off,
But time will tell as they say ,