A small notebook for a system administrator

Regarding 'rails to snap additional modules,' I was thinking that something like the mounting system for the Keyport multi-tool/ kickass gadget might be the way to go.

www.oxgadgets.com/2017/09/review-keyport-pivot.html

Specifically, their mounting system for the Keyport Pivot and its add-on modules:
www.mykeyport.com/pivot