Professor, The OP is looking for solutions to an issue and I'm really not familiar with that Holley, hence the questions. Too much spring load can contribute to his problem. Removing one return spring can be an indicator.
For some Holleys, part #44 is termed as such..........
FWIW, Not that it's not a good idea, or I'm bucking any race rules here. I'm not convinced Ma Mopar had a two return spring policy for many applications.
For example, if you order an "genuine official re-pop" return spring for a six pack, only one spring is sent to you ........
Unless you include a kickdown return assist.........
How they are termed as "spring" or "springs" is evident at these suppliers.........
Air/Fuel, Throttle Return Springs :Mega Parts USA
You searched for throttle return spring - Vans Auto
Back to the issue.......
OP, I recall my '77 pedal back side had worn a groove in it that contributed to peddle effort. You may want to look at that as well.
BTW, They didn't have back up torsion bars installed either. If you ever had one snap, would you wonder why not?