It may work 'ok', but if you've gone that far to improve the front-end, you may as well spend a little more to do it right.Your perfect spring rate depends on your weight+ the bike's weight.
Plenty of online charts out there to assist you: this bike with a full tank is about 235kg / 517lbs. Just add your own weight and you'll be able to work the revised spring rate out.Or post details and someone will advise...