Eric,
With newer bikes that have inverted forks you are measuring the actual oil level, that is the measurement of how far the top of the oil surface is from the top of the fork tube (with the forks fully compressed). I messed up on my earlier reply in that to change oil you must remove the forks to empty the oil. The 5wt is correct. Make sure it is for cartridge forks - which most is now days. Kayaba 01 should be the right stuff but any brand name (maxima, Belray etc.) equivalent will be fine. Unfortunately most bottles are 1000cc which is not quite enough to do both forks. For example, my 500 takes about 580cc per leg so I am 160cc short on a change with one bottle. Sometime I reuse 160cc from the cleanest part of the old oil (after you let any contaminants settle out) so I can make do with one bottle and not have most of the 2nd bottle sitting around. Hope this helps. Cam.