Well for that little NOS use you could get by with no extra I have sprayed way over 500 on a 440 with .022 top
These days NOS means multi stage and gobs of gas so that .007 is right for Street Outlaw kind of blast but...for what you want to do no big deal set it about .020-.021 top and let her rip never look back--
I still say that for decades strong race engines ran with tighter second ring gaps--these days they say open second ring to reduce flutter--OK OK it may flutter at 7500 -9000 RPM but IMO it ain't no big deal on a street strip Mopar of average build--I like to keep second ring tight
I can honestly say it "may " make a difference on a high winding big RPM ball buster engine but on average I think keep em tight and go on with it!
And the secret to the .590 is where you degree it in--done right it is one of the best all time Mopar grinds ever made--For a drag only we like that cam in samller inch at around 100-101-- and about 105 in a 500 plus inch--
do that and it will yank the slober out of your mouth! Retarded that cam is a noodle! Trust me in your CI I would install it at 100-101--
You will not need that NOS if you have the right converter and have enough gear!
Good Luck!