Here's my input FWIW.

The primary controls rpm. The secondary controls load feedback. If the primary has less resistance to fight from the secondary, it will become more dominant. Thus, will upshift more for any given rpm and potentially pull the rpms down.

Gearing affects how hard the secondary fights the primary. The lower you gear, the less torque feedback you experience coming back from the track into the secondary.

So, gearing lower versus stock, should cause the rpms to drop some, all else being equal. In fact, this is why I use a 340 finish spring on my lower geared 23/37 versus now 22/41 AXYS with 10-68 weights and a BMP stage I setup.

IMO, this is why you do not compare engine clutching setups between different sleds with different load feedback, rider weight, sled weight, track size, lug heights, etc, etc..

Set your sled up for what works for your unique situation.

 

Patrioticinovations gave you some good advice, and i will add a few things from my personal experience.
You have the funtions of the weights and springs correct, a higher finish rate on the drive spring will/should increase operating rpms but 20 lbs of spring is usually a smaller change than 2 grams of weight.
I am not an expert tuner or even a good one most days but i do try very hard to avoid going backwards without knowing it. Going by seat of the pants can fool you more than you think, if you make a change run against another sled if you dont have a timer. On a related note, clutch it for best performance amd note what rpms it runs best at, not the other way around, performamce should be end result not rpms. Most dyno pulls i have seen on one sled i owned showed the power peak at 7800-8000 and everyone on the fourum will tell you to clutch it at that rpm. Mine was sevral sled lengths quicker running at 8150. Never did figure out why, i was curious why but never did loose any sleep over it.