Joe, i'm not sure which color relates to what load the spring carries either. A victa gold dealer may be able to help you out there.
I suppose a heavier spring will give you a higher no load RPM that should hopefully not cause it to increase rpm so suddenly through the long grass. A lighter spring spring i'm guessing would have the opposite effect, like i said, i've never tinkered with one to give you an exact answer.
So, i suppose trial and error in this case may be you're only friend.
Keep us informed on how it works out for you.
Cheers, Ted
