That's right, you should only need to drop the forks down 3/8 or less. We tested these on our custom bikes with great success. The top tree is for stability and the bottom tree handles all the stress. You should not remove or loosen the stock fork caps. Please at anytime don't hesitate to contact us if you have questions regarding our products we would be glad to help.
As for the geometry your not really changing much, but if your worried about what the change does; Lifting the front of the bike will improve straight line stability and also break the wind better, you'll also improve ground clearance, so the pegs will scrap less. If anything negative the steering might feel heavier while at very low speeds. BUT again the change is so small you'll never notice. Lowering the rear with a slight raise in the front and a fat tire will make these Strykers ride very nice.
Thanks for your interest, please let us know if you have any questions, we are here to help you guys.
LM
LM