I posted a thread about steep climbing cadence a while back. I recently changed from a 14-32 cassette to a 13-34 cassette. I have about a 1/2 mile climb on the road to my house, which has an average of a 12% grade with as high as a 17.5% grade on one part of it. When i attack it, i'm pretty tired after being on the bike for about 1.5 hrs over 17.5 miles, with about a mile left to my house. I also have about 15 extra lbs added to the bike from my school books in my backpack strapped to the rear rack. Recently the best i can do sitting is about 45-60rpms in the lowest gear.
I'm young at 25, but still want to protect myself for when i get older. Am i better off to sit or stand during this climb? Which would be better for my knees and joints?