You can create arbitrary namespaces, but they are “temporary”, meaning they only have meaning for the script type that you are on. The values are scoped to that update, spawn or event and are not persisted in any way. We use Physics.Force for this. It is set to zero by default at the beginning of the update script, a bunch of force modules go in and accumulate their forces for the frame, and then the SolveForcesAndVelocity module resolves those into changes to Particles.Velocity and Particles.Position. Anything you create will follow that same paradigm. However, you can create sub-namespaces within the supported ones. So Particles.Cannabis. is a perfectly valid namespace to organize all your custom stuff into, which I think gets you most of what you want.
We reset the sim when you change values for now as we don’t know if the change is cosmetic or functional and just opted for the safest. If paused, we re-sim up to that point, but that may be flakey in the build you are using.