1971 Duster 360/727

So now I've done two test drives after breaking in the cam :-)
It runs like a beast but unfortunately it won't Idle that good, also runs rough on low rpms while gas is coming out the exhaust.
Gonna set the valve lash again since I put back the inner valve springs.

I got recommended to drive about 300 miles below 3000rpm and then do another oil change before driving it hard, does this seem reasonable?