Bob, David Goodson has what you need & you won't find anyone better to deal with. He's the go to guy for electronics, sales & installation, & specialty items like the mount you're looking for. He's a wealth of knowledge & experience.
'98 Tr20 Triton completly updated & rigged, 05 Magnum c-channeltrailer
'94 Merc 200Xri completly rebuilt & noseconed/low water pickup lower unit.