The lack of F keys continues to boggle my mind on these custom layouts. I need to be be able to mash F5 or F8 at a moments notice without any chording nonsense. Unless you are working from an ironing board, most desks have ample “vertical” space to extend towards the monitor with the extra keyboard row.

75% (84 key) is definitely your friend then.

It's similar to a lot of laptop layouts as well, so if you find yourself often switching between a laptop and desktop it feels quite natural.

I use a budget Keycool 84 (MX browns) and love it.

You could make a 75% version, but it would not be quite as nice :-)

I think my next design will have another column of macro keys, making 74 (my birth year mod 100).