I also used the external reference while learning (taped a printed-out layout to the top of my screen). One regret: like the parent commenter, I stopped drilli

I also used the external reference while learning (taped a printed-out layout to the top of my screen). One regret: like the parent commenter, I stopped drilling early when "fast enough". Then I asymptoted to comparable speed to my qwerty days (and greater comfort), but worse accuracy. Years later some further drilling was worthwhile to end up actually better at typing than in qwerty. Overall I'd say the Dvorak/qwerty diff was enough to justify choosing Dvorak when you start to learn touch typing, but probably not for switching later. The increment of improvement from Dvorak to a newer layout seems considerably smaller still, and I'd weigh that against universality of support.