On Friday, 5 July 2019 08:24:14 BST mad.scientist.at.large@tutanota.com wrote:
> Thank you!  Now I don't have to read all the grub2 manual right away.  

Hardly anyone needs to read the whole GRUB2 manual, unless you're interest to 
know the ins and outs of GRUB2.

However, it would be advisable to skim-read at least this wiki page, which 
explains which files you could/should edit to make GRUB2 do what you want it 
to do:

https://wiki.gentoo.org/wiki/GRUB2


> Works
> mostly like I thought but first attempt was to edit the mkconfig- grub.cfg
> and I failed to back it up Properly.  I should have tried it first on a
> system that didn't have 4 other distros laying around.

As per the above page, you could edit the /etc/default/grub file to define 
default variables, *then* run the grub-mkconfig command.  Depending on your 
needs you could also add files in /etc/grub.d/ or edit 40_custom.

You could create manually a /boot/grub/grub.cfg file, but this is NOT how 
GRUB2 was meant to be used.  TBH, if you want to do this, then why bother with 
GRUB2 in the first place.  You could instead install sys-boot/grub-static from 
an overlay and use grub legacy by manually configuring its /boot/grub/
grub.conf file.

https://gpo.zugaina.org/sys-boot/grub-static

Alternatively, there are other bootloaders to consider, with sys-boot/syslinux 
or extlinux featuring as lightweight alternatives.
-- 
Regards,

Mick