Adding fork oil

I have a 2012 R'2 and the right fork is leaking just a little bit the local dealer will fix it but5 I have a ride to go on before I can get it in the shop. He tells me I can add oil to it ( 10 wt ) and that all I need to do is compress the fork and back off the center cap . has anybody done this before ? thanks in advance...

The bike comes stock with oil that is 5wt, so unless the internals have been modified to run a 10wt, I wouldn't use 10wt.
 
Sure, you can add oil that way (it's even easier through the air bleed screw via a small syringe or needle), but the thing is, how do you know how much to add?

I will check with them again on the weight and i don't think I will need to ad more than an ounce or two for now