I think it just depends on the rifle, each is different and what works on one, doesn't necessarily work on another. This is probably all dependent on how good the fit of the barrel to the frame is and the lockup. I've used pressure points on a mannlicher forend to improve accuracy, others have done the same with the regular forend using business cards. Fully bedding seems to work also, as at least a few members have found, but that dedicates the forend to that barrel. My fluted .22-250 doesn't shoot well at all from the bipod regardless of the position, but it shoots fine with a rest under the hinge.
I've experimented with a shim between the spacer and the wood forend, it usually it helps, but not always.
In the end when all is said and done, do what works, but start out of the box with no changes, then do what's necessary.