What happens to the feel/action of the forks if you put in more oil than specified?
Will it make the compression harder?
Rebound slower?
Plusher feel?
Fork manufacturer says 5ml of 15wt per leg, what if i put in 10ml?

The lower oil is just for lubrication as far as I know. I wouldn’t add loads more but 10ml to 5ml is nothing.

The volume you really need to take care with is that in the tubes themselves when you strip and rebuild

Depends on the fork, a little bit.

Open bath Fox forks if you didn’t empty the damper fully, and then topped up with the correct amount of oil, they would limit the travel with hydraulic lock. They were very critical on the damper side.

The spring side you could splash loads about without any inconvenience.

Thanks for the replies, they are 2015 RS Revelations and its only the lower leg service.