[TSM]

Found this regarding spacer length. (TT from SVRider.com)
http://www.svrider.com/tips/emulators.htm

Now you need to calculate the length of the new spacer. I got some Schedule 40 one inch PVC pipe to make my spacers. Measure from the top of the fork tube to the top of the washers inside — in mine, with the emulators, Progressive springs, and both washers, the distance was 1.81 inches. The fork cap extends down into the fork tube about 0.70 inch, so that must be subtracted from the distance measured. Finally, you have to decide how much preload you want — I aimed for 20 mm (0.79 inch), based on Racetech’s recommendation. So the length of my spacer was: 1.81 — 0.70 + 0.79 = 1.90 inches.

What i found odd was this:

Carefully add fork oil (I used 20 weight, for a stiffer ride use a heavier weight) to the proper level, which is measured as distance from the top of the fork tube to the oil level. Race-Tech suggests 130 mm (5.1 inches); Progressive Suspension suggests a minimum of 140 mm (5.5 inches) with their springs, and that’s where I set mine. A homemade dipstick and a penlight help here. I made a crude dipstick out of a piece of wood and a nail to set the proper depth. Make a dipstick that you are sure you can't drop into the fork!

Most other people on here recomend 100mm from top with oil.