I bought the mount however they use a u bolt which is too narrow for the rail, so after looking at it, I removed a screw from the upper front bimini junction and slid it through the mount and re screwed it in. I'll take pictures next time I get to the boat. Works great and will pivot if needed.
Reel Ax - thanks for your photos of your install. It helped me to figure out where I would do mine. I went with a larger 8' antenna so I didn't do it quite like you did, but still on the bimini rail. I used the shakespeare ratchet mount and some hardware from Home Depot to do it. Pics in my gallery if anyone else is looking for a way to do it.