If I was buying a featherweight and HAD to choose between the 2 cartridges you stated, I would choose the 308 b/c of the short action and SLIGHTLY less recoil (than the 30/06).

But I personally wouldn't get either pf those rounds in a featherweight......a .243, a6.5 X 55, a 7mm/08, or a 257 Roberts would be my choices if going in a lightweight rifle.

The 308 wouldbe ok though.