If you are going to change the oil in the forks anyway,,, I would highly suggest getting a set of Progressive springs and installing them at the same time. I did this a few weeks ago, and the difference in the ride in amazing. It will be another $90 or so, but you'll already have the tubes opened up anyway, if you are replacing the oil. As stated above, you can change the weight (15# instead of 10#) but don't change the amount. You'll increase the likelihood of blowing a seal. And unless you take them completely off the bike, you won't be able to get ALL of the oil out. I bought a small hand pump, and pumped the oil out into a container, marked how much, then replaced the same amount with the new oil. You will also need the specialty tool for the left side (if you remove the springs).
Good luck,,,, and let us know how it went.
2007 1800T, Memphis Shades 21", Kury Engine Bar & Pegs, HondaLine Light Bar, Ultimate Seats, Cobra Slash-Cuts, Progressive 430 Shocks & Springs, HondaLine Saddlebags, Iron Horse Tail Bag, Fender Rail, Color-Matched Radiator Housing, Show Chrome Fringe, Kury Iso-Grips, Custom Breather Cover. GO TEAM DREW!!!