Bruce,
If you look at the blue 110 lbs spring and compare it to the stock D spring, the D spring is at 464 lbs at midway and 653 lbs at full bump. The short springs are slightly softer at midway, 330 lbs and the same at full bump, 660 lbs. So, the short spring has no preload in the first half of its movement and is "softer", but as your fork compresses, the rate of the short spring catches back up to stock and finishes at the same load.
To get back to the Comet, I chose 150 lbs. by using two 75 lbs springs. The stock Comet spring for the Bramptons was 160 lbs. I went ten pounds lighter because I was trying to accomodate all the singles, including the Grey Flash, which weighs 100 lbs less than the 400 lb Comet. Jan Wiley has used the short Comet springs for years and neither she nor the people who have ridden here Comet have found any fault. As a result, neither Sam nor I saw any serious issue with the set up.
It may well be that this set up is on the light side. A red and a blue spring might be a better set up, particularly for boys. It is a major reason that I had several springs made. There is no other way that I know of to adjust the ride height on the front end, so even though it may require another spring, it is a very small price to pay for the improved handling and limiting the prospect of a wobble.
Just as an aside, the damper determines the fork travel. The length of the outer spring boxes vary wildly. Mine looks like Kevin's, but I have never bottomed out the racer. The distance between the spring box attachment holes when the fork is at full extension varies quite a bit from bike to bike. There should not be any "play" in the spring box and you should have to compress it slightly to mount it.
David
