It's not a bedding block, it is a set of crossbolts-- the bolts are not exposed to the inlet. A hole is drilled through the stock. That hole is tapped all the way through with a long "airplane tap". A length of all thread is coated with Marine Tex and threaded into the tapped hole. The ends are covered in Marine Tex and the outside is sanded flat and painted over. The all thread avoids the "slick surface" that you describe. The end user will never know it's there but there are two crossbolts in the stock.
I'm the wrong guy to argue the physics of it but I don't think D'Arcy is doing it just for fun, he's not really that kind of guy. A guy who has built as many 458 Lotts as he has over the years know a little about the forces of recoil.
