We measure our closed spring pressure with the retainer, so we get the total spring pressure, just add the retainer thickness to your installed height. Also your spring supplier should be able to give you open pressure once you give them your valve opening.
Bill, I don't know your motor combo, but we replace our 1 1/2" dia PAC springs when they test on the car at 329 lbs. 330 is min with my 10,000 rpm motor at .938 lift, on the RR 23° SBC , new they install at 400. One of the best changes we have made was when I switched to the 1 1/2" PAC springs, they are more expensive, but I don't have to change them nearly as often as the triple springs. Unless we have some other problem, I only replace 3-4 springs all season.
Bud's non raised runner 23° only ran 260 lb springs. Our Hemi needs 420-440 lbs new, bigger valves, and high 9,000 rpm.
Back in the day when I had a dual engine BBC Top Gas car, and we wanted to be one of the 1'st Top Gas cars to go 200 mph, we did run 202 when we installed weaker valve springs, no other change.
So, if you are not sure what springs to run, check with your cam grinder, and be sure to tell them 9400 max.
Jon