I ran one Carter 500 on my hot 318 with 360 heads and it was just fine...down on power but ran fine all the way to 6500 like my DP Demon.
I now have two Carter 500's and feel power is right up there were the Demon was (after much tuning) I know for sure it idles better cold cause it used to stall the first few mins if it idle at 900 for too long without blimping the throttle now and then...now it idle just fine cold..both my Demon and Carters have no choke.
I would jet up the Edel two sizes in back...or just jet it to the manual 600 choke specs and go from there. Funny with two carbs the primary was very close..need a bit richer one step on both low and high power but have to go from .094 secondary jets to .077...I tried many combs but that is works best when its 80 degress outside or 55 degress.
BTW I sold my 750 Holley and my 650 Demon and all my metering blocks, jet kit and gaskets cause I see myself never going back to one Holley / Demon carb..why when two Carters make as much power but idle better and get 1 mpg more..and that is not taking it easy...might be 2 or 3 mpg better going a steady 60 mph. And I was a Holley lover for 25 years.