Carb CFM recommendations

Recently ordered a 318 long block assembly and waiting for it to ship. Getting the rest of the parts together to complete this build to drop into a 67 Cuda. The 318 is a standard LA block with stock heads. Upgraded to 9.5 to 1 flat top pistons, a mild performance cam (.450 lift with 272 duration and 110 separation), high performance valve springs and push rods and double row timing set. Everything else is pretty much stock. With a 4 barrel and headers, this engine should be around 275 to 285 crank hp, with a cam hp range from 1500 to 5000 rpms. This is not a race car. This is a convertible being rebuilt as a sentimental family restoration and we simply are looking for a daily cruiser with moderate performance and responsive drivability. I am doing all of this as a favor to a sister who bought this car in the 70s as a teenager. She is paying for parts only.

I am putting an Edelbrock 4 barrel performer intake and planning for an Edelbrock carb. I would love an LD4B intake, but everyone wants more for a beat up used intake than a new Edelbrock. For carb, the best options I can buy from Edelbrock are the 1406 which is a classic style 600 cfm square bore, or the new AVS2, which only comes in 500 or 650 cfm. 500 seems small to me, but 650 seems like too much. The sweet spot for this engine seems to be around 550, but that is not an option Edelbrock. I like the new design with annular boosters, but do not want to undersize the carb.

I should mention that we live at 5K feet elevation.

Any recommendations from experience would be appreciated.