My setup is based on a 6" diamater steel column. The MI-250 base plate has an 8" diameter. I bought the mount used and below is what the base plate looked like:
There are three countersunk holes that fit inside a 5.5" diameter and I decided to use them. The countersinks will be replaced with counterbores to allow the use of a button head sohc 3/8 16tpi screw
The adapter plate is a 1" thick aluminum disk with 6 threaded holes: 3 on the top that match the baseplate pattern, and three on the side, at 120° of each other. The slot in the baseplate points to the north. My pier's north screw is not quite aligned to the north and with the G11 I had to move the azimuth adjustment almost to the limit. To avoid a potential issue with the MI-250, I measured the offset while the G11 was still on the column and transferred it to the adapter.
Below are the modified baseplate and the adapter
