I simply do not understand the "increased performance" claims people in these situations make. There is no way.
All keyboards have fundamentally arbitrary layouts, some are just slightly more or less arbitrary than others.
I use dvorak, on an Ergodox at home and a TECK at work. My phone keyboard is changed to dvorak .
The only times I have to use someone else's keyboard, it's only for maybe a word/login here and there, I'm not typing novels.
I'm very happy I've switched to dvorak on ortholinear keyboards.
 Dvorak is not a great layout for phones, it's good when using two thumbs, but all the switching from left to right side is bad for single-finger or single-thumb typing.
I use dvorak, and I've found it a hassle many times just switching the layout of the various PCs I'm using into dvorak. Worth it, but a hassle. At least the dvorak layout is semi-standard though.
Custom dvorak is a bridge too far...