PDP F series 4” captured rod question

Hi everyone ! I have a 4” F series and wanted to reduce some of the snappiness of the gun. I’m looking at ZRTS captured rod. They recommend the 17lb spring not the 15lb. Does anyone have the 15lb in their f series and if so, does it reliably cycle ?

I just don’t know if a new rod at 17lbs will make so much of a difference from stock.

Thanks so much!

EDIT/UPDATE: Seems like the new captured rod is the ultramass rod now. Probably will just go with 17lb since it will be my carry gun.