In dynamic state and with associated random high amplitude, hairspring may stick.
A video of HS as you manually complement barrel power, would reveal such sticking. Should you set up for vid, I try to capture the guard pin as well.
No. The chapter ring is the one that may sit on top of the dial, with minutes or other markings. Perhaps you are referring to a spacer, or movement ring. Your NH35 comes already with one of grey plastic one. If it's size is not adequate, a watch manufacturer would replace it with a different one.
There are no standards. Movement size can be expressed in old French lines but that is just indicative, then each movement has a technical drawing for casing that show all the size including the very important hand and stem height.
If you are OK with bodging up an holder ring, there are assortments that you can buy, or use whatever common material at home. Otherwise making it perfect requires 3D printing, or precise metal turning and milling, even if hand made.