My right fork leg seal was leaking, which I managed to stop by using a homemade Seal Mate. In the process of pulling out the dirt from the seal, a LOT of fork oil seeped out. That's in addition to what's been dripping out since I bought it, as well as when the previous owner stored it (seems to only leak when it's not ridden). Is it possible to just top up the fork oil by removing the cap with the fork in place and just adding to a certain air gap, or do I have to remove the leg, dump out everything, and measure the 524 cc (right leg - Low Seat)? Lastly, the owner's manual lists SHELL Advance Fork 7.5 or Donax TA - the current oil is red in colour, so would that be the Shell or the Donax, or does it matter as long as I just top it off with anything 7.5 weight?