If I didn't have other projects I would like to work with a 243 Lightweight barrel. I believe the forearm stability, strength/pressure would be main culprit.
Sense most NEF/H&R barrels are cut to a heavier contour most all forearms are suited to this wider fit. And I think using these forearms for SuperLight contour barrels leave too much room. I believe a wood forearm would be easier to fit the contour with a little sanding to fit the barrel and maybe some bedding to solidify the whole package...
Though I won't speak for all, as I know there are many out there that have accurate SuperLights.
I wish I had the time to really give one a go with different forearms and loads...

-Aaron