Using Git for OpenSCAD and 3D Printing

Greetings,

If you were to design a new workflow, what key observations would you 
make in regards to OpenSCAD scripts?

As a quick illustration: I have a model with cavities to hold hex bolts 
and nuts. I fine-tuned the model to print on PrinterA, using FilamentA, 
SettingsA. Once in "production" I need to "freeze" all relevant scripts, 
especially when using multi-file structure. If the modules receive 
parameters I need to "remember" those parameters (such as the radius for 
the hex, and the dept of the cavity), and if they use hard-coded values 
I must remember not to change them. Otherwise I cannot repeatedly print 
the same model.

Now imagine this for the entire standard set of hex bolts - each of 
these were fine-tuned, test-printed and verified.
The rationale behind this to guarantee that the models trying to conform 
to a standard (such as ASME B18.3) stay put, while models receiving 
non-standardized sizes such as Nylon 6/6/ (which have bigger hex heads) 
stay separated, and tweaked to work with each supplier.

My question is, should I just "hardcode" everything, set up forks or 
branches for all past scenarios? So far I only have a few dozen models 
and I'm already having a hard time finding models I printed and used in 
the past, to print again. How do I structure all this?

I am a mechanical engineer not a coder, new to all these. Maybe git or 
revision control is not the correct tool for this job?

-- 
Thanks for your time reading,
Sandor