I had to drill 4 holes in the SS top plate for the control box screws to pass thru it to screw down back on the pedistal. The screws holding the top plate thankfully had holes in the top of the pedistal to scrw into, allthough they were so old and corroded I had to get the right tapping tool and run it thru to clean out threads. Obviously I first had to disconnect the control cables to remove the control box, it was pretty straight forward.
The guard typically comes at 58 inches -best to use a large pipe cutter to cut in down to the size you want. I determined that the GPS will not interfere with the compass even 6 in's away, Garman say 24 inches... But spend some time measuring to what height is best, better to make several cuts than too much too soon.
I fashioned a piece of starboard 5.5 x12 in rounded the edges and drilled two 1 1/8 in holes 9.5 inches apart to slide onto the guard to hold my Gps- I also bought 4 shaft clamps at Fastenal to secure this.
The feet went on well-just alot of placing and measuring and eyeballing... I drilled a 3/8 to accept the GPS cable, its all I needed.
use Git Rot in that hole to seal the core in the hole in the event of any water seepage.