We make these mounting plates, by hand, and sell them on the new site.
Edson Pedestal Guard Mount Plate (LINK)
Specifications:
Fitment: Edson 1" 9.5" Hole Ceter Pedestal Guards
Hole Centers 9.5"
Hole Diameter - Sized to fit 1" OD SS tube
Width 12"
Depth 5.5"
Material 1/2" White Starboard