Info on home made regulator please

[GarthThomas]

Ive been looking for info about cutting fill assembly shorter as well as the valve assembly to gain volume for a regulator in my Cothran 2260 hpa tube. I see one vendor makes a shortened valve but I dont use a gauge so I though it would be possible to make it even shorter.
While looking I came across a post by rsterne from a while back https://www.gatewaytoairguns.org/GTA/index.php?topic=26561.0
I was wondering if this was a viable option, the power is where I would like it. Right now Im getting about 20 good shots but the curve is so big even my ssg hasnt made enough improvement. I was hoping to find more info on dimensions and even an internal drawing of how it looks together. If someone knows of another link on that subject and also about shortening the other assemblies I mentioned. One o-ring should be good enough, I’m not planning on going over 2000psi even though the Cothran tube can handle it.