It’s tricky, because you have 12 different branches of code. If you could somehow have one version of the code, and the users had to download it, and then copy a specific example configuration/configuration_adv for their setup, then this would be easier for you.
In Git, a branch is a moving target. It can be moved and describes only where that code is right now. So MPCNC_Rambo_T8_16T_LCD_DualEndstop is pointing to the current version.
Tags, however, are pointing to a specific version, forever. That’s typically how someone would point to v1.1.9, for example. 1.1.9 isn’t ever going to change.
You could make a tag like MPCNC_Rambo_T8_16T_LCD_DualEndstop_v403. But pretty quickly, you’ll have so many tags that they will all be lost in the cruft.
A way to simplify this is to change to fork into two different branches. Something like the ones you have now will need to stay on a stable version of the code. They won’t follow the latest changes, and anyone who just wants to cut some stuff will have to settle for this stable version of the code. Then, you also have a single branch for testing, development, and the latest Marlin features. You can call this something like ‘beta’, ‘unstable’, ‘wild_west’, ‘devel’. If someone wants to use that bleeding edge ‘devel’ branch, they will have to do a little work to configure it from the vanilla to work with a MPCNC Rambo T8 16T LCD Dual Endstop. If you decide your devel branch has become stable enough to make the base, you can fix your 12 stable branches to be based off of that, and move your devel forward.
This might become a lot simpler in a short while if they “release” 2.0 and you can base your branches off of that. Tracking the bugfix branch has meant we are getting some features earlier than otherwise, but we’re also getting new bugs faster than otherwise :).
As far as editing the configuration.h and version.h, that seems fine to me. Making a _Version.h like they are suggesting would mean you’d have to set the flag, which I don’t see a good way to do that unless everyone switches to platform.io.