A little late but to echo some thoughts:
I have an identical setup. I rafted the Main Salmon alone with it and it handled fine (as far as length and dimensions); I was carrying a ton of group gear that trip.
My wife and I run Class III-IV multi-day trips (5-
with the rig 1-2 times a year. I have run Westwater twice, Deso 5-6 times and Cataract (below 10k) twice now with the boat. The critical point is definitely not getting the water into the floor/frame lower bars; its get really sluggish then. Seems to happen around 800 lbs with the post-2007 tubes (more rocker and less volume).
The Main has some great assets for such a boat:
1) Carry very little water. We pumped at camps with a gravity filter. That saves 75 lbs per boat.
2) Most of the rapids are straight forward with tons of entry time. That was before the new 2010 rapids though (they still look like 1 move pool drops though).
1) Offer to be the liquor bar if someone will carry your beer. The front box makes a great and easily accessible bar table for cocktail hour in camp.
2) I often carry everyone's chairs in my drop bag (as a share of group gear). Most rafts don't have to worry about weight but bulk can still be a problem. That wider frame makes it easy to shove everyone's chairs and tables into a no-hassle drop bag. Between #1-#2 you can save 50 pounds in comparable gear.
1)Passenger has to be very dynamic with highsiding without the comfort of a floor or surrounding tubes. My wife has gotten quit good as this.
Best of luck with the permit. Don't think I would want to be in there mid-May to Mid-june with that rig but the rest of the year should be great. I love my Ocelot and will likely keep it for life.