https://www.avtecdental.com/mini-fix...-dci-9155.htmlI had an idea , using one of these as a pressure regulator for brakes before brake valve. That way I always would get a max 35 psi for brakes and still could use 100 psi for rest of the system.

doable?

not very expensive but shipping is 25$ to europe..
And looks small and lightweight solution.