I'm very confused about an 80% that allegedly moves ANY keys other than navigation, numpad, or f-keys. Any 65% will meet your requirements.
As for <60%: use that neuroplasticity. Stave off dementia. You can do it.
As for <60%: use that neuroplasticity. Stave off dementia. You can do it.
There's neuroplasticity and there's picking your battles. :-)
My layout would not work for you since I put navigation on the right hand (close to where it would be normally), but do whatever works for you.
Personally I use navigation keys much more on my split because they're right under my fingers. Having VIM movement keys everywhere is quite nice.