Thanks for your help, next step learning to do particular series like yours with particular car updates and setups assigned for each track.
Making basic rfmods are pretty simple to do.
The problem is saving those rfmods for easy updating because the files are overwritten in roaming.
I use a what appears to be complicated system but it's actually pretty easy and takes far less time then redoing big rfmods from scratch, especially when you have 26.
Car Updates can be enabled and disabled within a rfmod before session.
Assigned setups is done automatically if you save them and click assign and favourite, when you come back to that combo setup will be selected, same as your seat, mirrors and FFB.
Worse thing is making many rfmods from full list of content is easy to make mistake miss a car / track.
TIP: When selecting a heap of cars and tracks for a mod.
Make a shortcut on taskbar for onscreen keyboard.
Open MAS2 and click on first car
Now click Ctrl on the onscreen K/B
Beats holding onto Ctrl forever
Just make sure remove Ctrl as soon as you finish selecting all content.
ALSO: Be aware you can select content by individual track layouts and skins, just unpick the boxes you don't want in rfmod.
Like you don't want a oval with road course mod.
Also watch out for go karts and FE layouts

I know I say below don't open rF2 making mods but if you making a new one you can open it in a small window
so you can see the car # and colours like say if you want a reduced field.
Using just MAS2 this is not easily discernible especially when all the numbers are mixed up in MAS2 but in order in rF2 menu.
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This is the folder and files from roaming you need to update a rfmod.
~MASTEMP and pkginfo files can contain only info for one mod at a time.
You can keep making rfmods but sooner or later ( 4-5 rfmods ) MAS2 will crash and won't be recoverable till you remove the pkginfo files.
So like you see in my list I have one set of files for each rfmod.
When I want to update a mod I use OVGME to inject those 3 files into roaming.
MAS2 will open with that rfmod ready to alter / update.
After you have updated the rfmod you copy the files from roaming back to it's OVGME mod and overwrite the old.
Never leave rF2 or Steam opening while editing rfmods.
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