I just want to show you one the layout I create: BvoFRak EN v0.4.
It's only based on statistical elements.
The aim was to increase "rolls" in english and, use it, to create one close to my mother language (french). On paper, it could be a good alternive in english (good alternation of hands, low use of the same finger, low distance and good rollings) . In real, I don't know…
Of course, you can change the position of red and orange secondary keys (Ⓥ↔Ⓛ↔Ⓜ) because, like me, some find easier to reach the bottom line with the index (in qwerty Ⓥ) than to move the entire hand to reach the upper line (Ⓡ).