The one I installed on Cbreeze is solid copper 20"x 6"x 1/4" with 4- 1/2" silicone bronze bolts. Barnacles
love it. Recent thinking is that the plate edge is where the discharge is supposed to occur so I started painting mine and then scrape the paint
around the edge before launch.
Bought the plate from Storm Copper and soldered the flat head
bolts to the plate before I installed it. Two conductors from the bottom of the mast
to the bolts. The copper plate is just in front of the mast