What are you trying to do, firm them up or reduce the harsh damping?
I've tried a few things with not much success.
My forks ( on a 2014) had what looked like 7.5-10w oil as OE and a 120mm air gap. Changed to 5w and 135mm and Hagon springs, never felt right, high at front, back to OE springs and while better it wasn't worth the effort really.
There are two other threads on the first page here discussing it.