I recently made a sunken foot board for my XK120 FDHC. It is an alpha test so it’s not ready for ‘prime time’, but here it is in rough shape.
I used 1/4" felt under the metal floor to gain a bit of height and fashioned this to provide more foot room.
As I said it’s the first test model, but worked out pretty well, I think. I missed a hole of two for fastening it down, but that will be corrected. I’ll eventually POR15 the bottom and seam fill the corners and paint it overall. Currently it lays on the frame, but there doesn’t seem to be much abrasion that will happen - on smooth roads anyway.
Anyway, I am always thinking of how to improve on the obvious problems with my basket case FHC.