I've got .26 springs and have a 60lb rider, the .25's were bottoming way to easy even with 15wgt oil. I know have 250cc per fork (15 wgt) trying to slow the compression with heavier oil. I may still increase the level since we haven't tested on a mx track with the .26 springs.
Next step is have a suspension guy work on the damper tubes is these changes don't make me happy.
I will be getting an oil level gauge after this weekend of racing, it is a much more precise way since you may not fully empty tube of oil.
Steve