I've been playing around with different layouts for special uses. Haven't necessarily decided the "ideal" solutions, but the basic concepts themselves are worth considering.
There are plenty of times I'm not typing, but I am working on the computer - probably mostly using the mouse. But I may need to do something on the keyboard quickly. I don't want to grab the keyboard (on it's little lapdesk) and use two hands to do some things. I want to be able to just reach out with one hand and get the job done.
One approach is to use the function layers. Depending on how you set them up, I could activate a layer (holding K and L), while using my index finger to hit U (volume up). So only one hand needed. But you are limited in how many keys you can hit with one hand. And, of course, if you are using a lot of the function keys anyway, some of those spaces aren't available.
But recently another Treg tester - sorry, I forget who - suggested I look at the emoji layer.
You see, besides the chords for command, control, option/alt (duplicated on each side of the keyboard), you can also set up "hot corners". That makes the left corner of the space blade a "command" key and the right corner of the space blade an "alt" or option key. But if you chose the emoji layout option, that right corner instead activates the emoji layer.
As it happens, I've never used the "alt" option on the spaceblade so I decided to switch to the emoji layout. Had to change a lot since it is based on qwerty and I needed it to be dvorak. But once that was done, I selected just a handful of emojis (I rarely use them and, if I do, I don't need more than a small number). That left me with lots of room on both space blades for other things.
All my emoji are on the left side so would take both hands to access (usually). But that's fine since I'm only using them when typing normally. The ones on the right side can be controlled with one hand.
So instead of putting things in the function layer, I put them on the emoji layer for one handed use. Some spots are easier to hit than others so that's where you have to decide what is best for you.
Things I'm looking at now include:
The three volume controls items (up, down, mute)
Screen brightness (brighter, dimmer)
Bigger text / smaller text
Close active tab
Show desktop, show all windows, show windows for active app
Copy screen to clipboard, copy screen to desktop
Copy a marked section of the screen to clipboard or desktop
Turn off the TextBlade
I'm not planning on making all these one handed operations, but some will be. Some, such as turning off the TextBlade, I'll want to require two hands.
There are also sometimes a need for a one-hand "undo" - like when you play a game and want to undo a move. Also one handed paste. I've found that sometimes using the mouse doesn't always paste exactly where I want it, but the keyboard will (after placing the cursor with the mouse).
Near as I can figure, combining the emoji with the two function key layers, there are 33 places just on the right blade where you could put controls without having to resort to the "sticky" for the function chords. That's a lot of one handed capability.