I've got one of these; I plan to re-mount the adapter itself to an a Century lens board extension so I can use it on my Century Graphic, then I can use an adapter to put it on my Graphic View if/as needed. My Speed Graphic is an Annie and it's difficult to set the infinity stops to the 112 mm flange distance the RB/RZ lenses call for.
The board them come in, IIRC, is for a Linhoff compatible.
BTW, the RB lenses shorter than 127 mm don't even come close to covering 4x5, but all of them will cover 6x8 and the 65 and longer cover 6x9 -- and the Century is a lot lighter than my RB67 (but this idea has lost some of its attraction since I got a decent Gitzo backpack that will haul my RB, waist and prism finders, three film backs, a 50/90/180 lenses (or I could trade off one film back for the 127 when I get its shutter fixed, or replace the 180 with my 250).