I think that anything that tall (and thin) needs guying. I could be wrong but that's been my experience.
The pole in the picture is extended to 26 feet. that seems to work well. Its just not pretty.
Since you don't want to acknowledge the posts telling you that any *long* pole needs to be guyed, then quite frankly you need to decide which way you want it, and you can't have both.Short mast = no guysTall mast = guys.
Fire marshal inspection and no building ground equals no mast - that's that short and long of it.
I'm considering ordering 2 more of those water filled non penetrating roof mounts and just going with a 10 foot or so mast. Height = hassle.
Well you're already 3 stories up, so its just a matter of getting the signal off the roof and you're all set.