Yes I agree Snowy! You should always do changes in increments.
I didn't do the oil when I did the Hyperpro springs for that reason and also since I'm light I didn't want to change the compression damping (and rebound which I generally prefer fast). I suggested it for the OP since his oil will be due for a change since it's a 2009.
Although the theoretical weight difference between 7.5wt (stock) and the Hyperpro 10wt. is possibly "virtually undetectable" especially since it's not standardized, riders say they have felt a difference in feel for the better. If only fork oil weight was standardized that would make it all much easier. Then there's air cap as itsatdm mentioned.
Go by the "book" for starters...
I also forgot I wasn't going to post suspension info without my weight etc!
I'm about 170lbs. (77kg). with gear. So at the lower end of the spectrum. I ride fast and fairly aggressively on dirt (only one dent in the front rim though!) so that will affect the set up too and then there's rider preference. I'm happy with the improvements the springs made.