Experimental using a gsx shock, du to the rs250 swingarm.
The spring needed to be stiffer, so tried a idea

First thing to do was getting a usable diameter witch was smooth and not the casting smoothnes
So the whole shock in the lathe to get that usable dimension

And Walla here you have it straight/smooth so the fill ring can glide on it

Made a 16mm extra fill ring to get the spring stiffer

Made it so that the original adjuster rings can be used and the spring alignment is in center

And here you have it back as set

Its looks close, but seems to work at a normal rate