I've used those TAPCON screws for holding down molding strips on my concrete floor. Only hard part is not reaming the hole too large.
Hmmm . . . I have some of those. I guess you have to be extra careful about getting the mast plumb when you put those in - cuz once they're in, they're cast in stone as it were. I'm guessing you drill the first hole, screw the first Tapcon in, then get out your level and get the mast plumb before you mark and drill the second hole. Or is there some way to fudge to get the mast plumb once you get the plate screwed to the wall?Yes, They are hollow but they are Industrial cinder blocks used as walls to seperate property lines.
I use 6 Tapcon masonary screws per mast (4 corners & 2 in the middle) in most of my installs here as 90% of residential homes here in Phoenix have block walls instead of wood fences like they have on the east coast.