I built mine to adjustable, with oval radial bolt down points that allowed a small amount of rotational adjustment via jacking screws, to compensate for any settling of the pier or slab at a later point, I also insulated the per from the surrounding concrete slab with foam strips to eliminated vibration transfer of walking around etc. Oh, the picture is still here...
https://www.iceinspace.com.au/forum/...5&d=1170320323
Its an old picture of the pier made for my lat in the process of fabrication, but if its not too late, the image maybe useful.