Glad to see you've got it sorted. Are you running the EPC valve on your accumulator?
Also, since you've good some good documentation on your oil pressure before, please let us know how does with the upgrades.
lastly, I recently bought a 3qt accusump myself. My system is a bit different but not much. When I looked at the check valve for the accusump (brass 1/2" NPT), it seemed pretty restrictive. I asked a few of the vintage racer guys that use them and they all said they lost some pressure when using the canton/moroso check valve. They recomended an Earl's hinge style. I finaly found one at Hoerr racing. It hasn't made it here yet. When it does I'll take it apart and get pictures. Otherwise I'm trying to put the oil from the accusump directly into the oil galley. Thinking of teeing outlet to rear by distributor and at the front.
That melling 10550 is a great pump. I've used the 10552 and really like it.
Really nice car
keep us posted