Speaking as someone who's still struggling with the extensor tendinitis he developed as a young programmer over 15 years ago, with hundreds of nights of pain and hundreds of thousands in lost earnings as a result...
First: It's a natural hacker impulse to focus on keyboard layouts and hardware and other fun toys like that. Resist that urge. The importance of that stuff is tiny compared to good overall ergonomic habits, good posture, taking breaks, and managing tension. Get all the help that you can on those issues. Watch your own habits. Have someone else watch you. Make adjustments.
Second: Having said that... when I was first having hand trouble, I switched to Dvorak. This was, for me, a very poor decision. As you've noticed, Dvorak overloads the right pinky finger, which is a bad idea on a typewriter, but a horrible idea on a computer keyboard where other often-used keys are on the right edge of the layout.
Moving the entire arm to hit Enter and other right-edge keys with a non-pinky finger helped some, but not enough. After a couple weeks of increasing right-pinky pain, I simply swapped the L and P keys, so the commonly-used L was on the left index instead of the right pinky.
The L/P swap helped with the overloading, but exacerbated my second problem with a new layout, which was greater tension while typing. Even though I felt comfortable with Dvorak on a conscious level, I was still sometimes tensing up before keystrokes as my fingers weren't sure which way to go for an extra few milliseconds. And I was still having to use QWERTY keyboards often enough that I couldn't completely banish that muscle memory. Eventually I just switched back to QWERTY. More finger-mileage, yes, but is finger-mileage really the issue? It wasn't for me.
Third: No, really. Spend your time on the annoying difficult-to-scientifically-analyze meatspace issues like posture, not on keyboard layouts.