I have also considered no springs at all - which would mean that the metering rods would only rise with throttle position.

The cam is a long way from stock. Stock spec is 220/231. I found an old Isky spec in his '56 publication:

Specifically the (dual pattern) DP#2
Iskenderian advertised it as a 250/280 affair.

I asked the guys at Delta to regrind a cam to the Isky DP#2 spec. The cam doctor report for the stick indicates:
248/264 @ .020
205/233 @ .050
Lift is .41/.40 with stock 1.5:1 rockers.

It's a 'moderately tight' stick (from Grumpy Jenkins perspective) with a LSA of 107.5. So I was expecting some lope . . .