These differences between people are really interesting. When I switched from a traditional keyboard to a flat column stagger keyboard, I did 15-30 minutes of exercises a day and after a week I was pretty much at my regular speed. Going from a flat column stagger keyboard to a Kinesis Advantage took me a few hours of adjustment at most. And from the Advantage to the Glove80 no adjustment at all.
I type Colemak-DH, but I am experimenting on the side with letter on thumb layouts. Over the past few weeks, I have tried rsthd, Maltron, and now aptmak (30 key variant). With aptmak I am at 40 WPM after ~5 days. I still type Colemak-DH during the workday at my regular speed, I can switch to a typing tutor and type aptmak at that speed again after two minutes or so (even though I have space on the other hand).
I am sorry for all those people for which this is a really long painful process. I am sure age is a factor, but I am also past 40, so it's definitely not the only factor.
I type Colemak-DH, but I am experimenting on the side with letter on thumb layouts. Over the past few weeks, I have tried rsthd, Maltron, and now aptmak (30 key variant). With aptmak I am at 40 WPM after ~5 days. I still type Colemak-DH during the workday at my regular speed, I can switch to a typing tutor and type aptmak at that speed again after two minutes or so (even though I have space on the other hand).
I am sorry for all those people for which this is a really long painful process. I am sure age is a factor, but I am also past 40, so it's definitely not the only factor.