My suspicion is that whatever efficiency gains are possible are going to be wiped out by the difficulty of learning a new system and then also not being able to readily have your preferred layout everywhere.
Not readily having the preferred layout available is a non-issue. Either I'm using a keyboard for less than ten minutes, in which case I hunt-and-peck on QWERTY, or I'm using it for longer, in which case I switch to Dvorak using the OS keyboard settings. It's never been a problem on Windows or Linux. I don't think I've used a Mac during that period but I imagine it's equally easy.
As I recall the awkward learning period was between a week and a month. Twenty years later I've never regretted the time invested.
I also was learning piano so that may have been a factor.
Personally, I have been learning to touch type and used the opportunity to use an optimized layout. I have recovered almost all the speed of non-blind Qwerty within a month and plan to stay.
Not being able to use it everywhere is not a drawback to me. For those rare events where I cannot use it, I still have more than enough muscle memory for Qwerty.