I made 25 mm slider extensions for my N15. It has already 25 mm longer stanchions.
It definitely is an improvement, especially on rougher roads.
They are hidden inside the chrome (now stainless) shrouds:
Making them myself, I could machine them to the size of the seals I wanted to use:
ARI. 149 (35 x 46 x 11)
ARI. 003T (35 X 48 x11) OD must be reduced slightly to fit the sliders.
Ariete seals are much better than std seals.
By limiting the extension to 25 mm, the top bushing still extends into the slider itself,
Thus under emergency braking, the load on the fork will be divided between the two.
(probably doesn't matter, but I like the idea..)