Picked up a well-used hex to square adapter at the pawn shop. Decided I'd modify it so it wouldn't just push on thru the wrench.
Drilled and tapped a hole in it and then attached a countersunk fender washer. It looks like it was originally a 9/16" hex, but is so worn it just slides into a 14mm hex. So now I can use 3/8" drive sockets with a Gear Wrench, ratcheting DB wrench, or reefer wrench depending on the need. Total cost: $1