The Dayco Ultimax II number is 140-4748 which mean 1.4" wide and 47 and 48/64th's which is obviously 47 3/4" long. it is the same as the 0627-020 which is the stock Arctic Cat belt. To remove a belt lock the brake and rotate the back sheave of the secondary, then grab the top of the belt about halfway between the clutches and give a swift upward pull, this will pull the belt into the secondary sheaves and give you enough to easily remove the belt. As far as the belt deflection after a new belt is installed, make sure you run the sled briefly to engage the belt. Then check belt deflection. To adjust the deflection remove shims from in between the secondary clutch. If you want to measure a belt use a flexible tape measure and measure the ouside of the belt. I could go on and on here, but this should answer most of your questions.
Dave I don't care what you ride, and I can guarentee you don't ride as hard we cross country race, your alignment is off. Unless your using really cheap belts, or are purposely burning flat spots on the belt. Your offset should be 5/8" or use a Arctic offset tool and check it. As your belt wears use the shims in the secondary to keep the right belt height and it will last a long time.