In reality there is no real straight answer to bushing a rocker to make it right,since to actualy make it right it needs to be done custom on each rocker and to each valve on each head.
The reason is that a less than perfect sweep comes from a whole bunch of tolerances stacking up.
Rollertipped rockers has an advantage in that even if they are alitle of center on the valve they are not trying to push or pull the valve anywhere from friciton.
To the op,check what rockers clears your springs and retainers,dont take this for granted just check it,you dont even need to rotate the engine to see it,just lay the shafts in the stands,the point of contact is usualy betwen the retainer and underside of the rocker in the corner where rockerarm meets the shaft. who knows you may be able to shorten your list of possible rockers by just doing this.
Im still a Crane golds fan.