The intent is "be able to press F1-F12 without having to move hands so far from home row"; it's not "I want a smaller keyboard and don't need F1-F12".
For example, let's say you need to do Shift-Option-F12. First, you need to hold a modifier to bring your F key layer, possibly a separate or chorded modifier to get you to the F-keys above 10 since you only have have 10 numeric digits. Then, that needs to be compatible with both your shift modifier AND your option modifier, which with only 2 thumb keys per side it probably won't be. So, then you think, oh no worries, I'll just set up a single shortcut that does what I need, but then you end up with a profusion of shortcuts that you need to remember.
I've found that in practice, I can't really go much below 58 keys and 3 layers without requiring tap-and-hold or losing some of my less-frequently used chars (` comes to mind), so I can sympathize with the ancestor posts.
It's "I don't mind moving my hand to hit the key" vs "I don't mind holding down some Fn key to hit the key". (Or with F1-F12 on Macbooks, you need to both hold down a Fn key and move your hand).
For an example of "36 keys ... how", I think the popular miryoku layout is fascinating. https://github.com/manna-harbour/miryoku/tree/master/docs/re... -- Often, mnemonics for particular keys aren't all that complicated.
- Layer transition fatigue: If you have many layers, it can be difficult to remember which key(s) triggers them. This can be improved with time and practice. In addition, you might want to arrange the symbols on your layers to minimize the amount of layer transitions needed. For example, if you type ./ a lot if would be nice if they were on the same layer and either a roll or an alternation.
- Awkward finger patterns: if we go back to the ./ example, if for some reason you decide / must go on another layer, then you probably want / to be close to period. If you design your layer in a way where / ends up under qwerty P, then you’ll have to contort your fingers to make the ./ pattern. This gets way more complicated when you consider all the possible symbol patterns such as ->, =>, :=, </, ./, [i], [j], |>, (“, “), ):, etc…
- Unexpected layer transition same finger usage: people will sometimes naively put layer transition keys in suboptimal places. For instance, if you use right thumb for space, then I would argue it’s a bad idea to use another right thumb key for shift. The reason is because in between sentences you put a space after the previous sentence and then press shift to capitalize the next letter. If they space and shift are on the same finger then you will probably find this sequence uncomfortable. A similar logic applies for backspace. I would argue space and backspace should be on the same thumb because they are pretty much mutually exclusive. Also your space thumb is used to repeating, and backspacing often involves a lot of repeating.
Overall, I think layers do have a lot of potential to work, but I feel like there aren’t many tools to help people iron out all these subtle issues. I’ve been working on making such a tool, but testing it takes a lot of time due to the first point.
