Nice solution.
Could one not use grub screws (they come in 3/8 x 3/8 24 and are available off the shelf) with allen socket, they come in both stainless and HT or do they need to be brass.

"I don't know why these aren't available off the shelf... Not only do they provide for clearance I need but I think they look 100% better then those tall plugs do. My plug is on the right."