Hi, I have just recently started to look at "non-standard" keyboards, so please bear with me. 
I'm looking to replace my standard qwerty keyboard with a split variant, with no thumb cluster. Why no thumb cluster? My thumbs can move more than is good for them, which is making them hurt. So I want as little thumb action as possible. 
I saw this similar thread, but it ended up with thumb clusters:
https://geekhack.org/index.php?topic=120553.0Having no thumb cluster should also leave space for a handrest bar with a built in mouse, next to the keyboard, I think. 
What I think that I want:
* Split 
* Ortholinear or column staggered 
* Number row 
* Function keys optional (I will layer them on the number row) 
* Numpad optional 
* No thumb cluster 
* "105 keys" letter layout (see key left of Z and close to Return) - I believe this is called ISO?:

Soldering or 3d printing is no problem. 
I have seen keyboards that I think come close on keeb.io, but they tend to miss the key left of Z. E. g:
https://keeb.io/collections/foldkbEDIT:
Maybe the simplest is two halves, supporting at least 6x5 and 8x5 keys respectively (and preferably ISO Return key).