I have a permanent setup in my Florida observatory- lots of sand base.  Cement pier goes from 4 feet below ground up 10 ft above ground where an adjustable steel pier is on top of it.  Then my AP1100 mount where my C11" EdgeHD sits.  Checking my polar alignment over the past 2 years, I've only had to adjust it 4 times using SharpCap.  Even at that, it has never been way off.