The single thumb-shift is super-comfortable. For modifier thumb keys that combine with keys on both sides of the keyboard, like Shift, it helps to have them in the more central, inner positions, which is why Shift is positioned where it is. From there you can easily hold shift with your thumb and your hand still has freedom to reach any key - especially on a minimal board designs.

Where I think your have a fair point, is when commonly needed modifiers are in the outer positions and then combine with alpha keys on the same side. I have previously experimented with shift on the outer thumb key (i.e. switching Shift with Extend),  and it's certainly not as nice, especially for reaching inner alpha keys like G and B for example. It's still OK for the less frequent combos though: Extend-G and Extend-B are much less common than Shift-G and Shift-B after all.

Basically the solution to that issue is to design the outer modifiers and layers so that the most frequent keys they combine with are either on the opposite side, or at least, not on the inner-part of the same side.

> Super

It's the Windows key, I should update the text to make that clearer.

Glad you like the look of it - I'm still using this configuration as my daily driver and it's working well for me!  Having a good selection of thumb keys (min 4 but ideally 6) is the.. umm.. key to reaching to reaching keyboard nirvana!

Can't see any problem with flipping the symbols layer, except maybe that people usually use numpads (pin entry, phones, etc) with their right hand, so left might feel a bit unnatural at first, unless you're naturally left handed.

I haven't done much with dual-role keys. I once tried dual space/shift, but it didn't work out. I don't think space is a natural fit for dual role because it's too common, but other options might be viable. I quite like modifiers as OSM/sticky, which precludes using them as dual role.

What kind of keyboard will you be getting?

Seniply uses 4 as a minimum, but I think I say somewhere that you can use a third thumb key on each hand as an alternative for the Function and Symbols2 layers, rather than using the two-simultaneous-thumbs method. I kept it to 4 to maintain compatibility with standard(-ish) hardware, where you can just about get 4 usable thumb keys, especially with a split-space (but otherwise traditional) board.

My Matias Ergo Pro (which I was originally using Seniply on) failed a while back, so I am exclusively using Ergo boards these days. This means I always have 6 thumb keys, and have started to rely on them. Probably most people who would consider Seniply or something like it are using Ergo boards too, so maybe I'll update it at some point to make the 6 thumb-key option more prominent.

There may be some minor issues with having space on the left:
- assuming you keep Extend on the left also, Extend-space (for enter) won't be nice. You could remap it though - but I have to say, Extend-space is one of my favourite mappings!
- on standard hardware you'd need to remap the Function and Symbols2 layers as well since those combos are chosen to not conflict with space. On a Kyria should be OK though.

How would one achieve Ctrl-Shift n using seniply (on an atreus)?

More generally, how does one make use of the Ctrl-Shift key on the extend layer?

I have to press Extend - < to get Ctrl - Shift, but then how do I get the n while I'm in the Extend layer?

I'm probably being daft, but I can't see how you do it!

Many thanks! That did the trick.

I can see how sticky keys (is that one and the same as one shot modifiers or OSM) allow you to use final keys in the base layer, but how do you use a non sticky key like the C+Shift on the extend layer below the down arrow key? Can you only use that with other keys also on the extend layer?

I find it works well. The only sticking point is the timeout - might be less than ideal if you type Extend-T, and then forget. QMK can be configured with a timeout but I don't think it's currently possible in Chrysalis.

Apart from that minor issue, I quite like using the sticky Extend modifiers! It's the special sauce which makes 34 and 36 key layouts viable.

Yes, that looks right. If I do (using Ubuntu):

(Extend down) (tap a) (tap t) (Extend up) (tap t)

I get a new terminal pop up.

Is that definitely the right shortcut mapping on your system?

Can't really explain it. Different versions of Chrysalis? Or different behaviour in the OS - maybe there is a sensitivity on timings on key up/down events for certain operations. Mysterious.

ooh, interesting! Is the chrysalis stuff on github up to date with this?

Steve, you don't happen to have an image of the prior arrangement do you (symbols 1 & symbols 2 before your rearrange)? I'm trying to figure out what's different. Also, how are you making these nice images? Have you got a tool to automatically produce them?

I don't find all those symbol mappings intuitive, but thay may just be me?

Do you ever use the not symbol (¬)? Mine just sits there in my AltGr+Shift layer, gathering dust since 2009 or so. Heh.