here is more info on his guitar:
His tuning is as follows from top: D-G-E-C-A-G-E-C-A-F on a Derby Lap steel guitar.
This is a one of a kind lap steel made by Charley Stepp owner of Derby Steel Guitars.
It is a 10 string guitar built on a 12 string body.
The wider spacing helps with bar slants.

He founded his own business, “Robinson Graphics,” and designed a lap steel guitar which has been custom built for him by Charlie Stepp of Derby Steel Guitars in Kentucky.
Bebop