I think a .060 relief would cover any shrouding issues.
Also, on a simple bang for the buck, installing the larger valves, shrouded or not, bowl ported or not, is still a win win.
Of course as the official said, the more extensive work done the better the returns. No one can argue that. However let it match your build and not over run your wallet.
A far reaching example would be fully ported W2's on a mildly cammed (XE262) 318. But you get the idea.
