In my several decades of experience sitting at desks writing code and staring at screens, I’ve found desks and chairs fall into two groups: ok and miserable. If I can sit comfortably for a couple of hours I feel productive. I don’t believe a different chair or keyboard setup would give me a 10X improvement, or even 2X. With so many other ways to improve my productivity — including not sitting at a desk for too long — changing my seating position or typing setups falls way down on the list of things I would experiment with.

Anecdotally I’ve worked with a few people who spent a lot of time optimizing their work environment, and even more time telling everyone about it and making unsupported claims about their greatly enhanced productivity. I have not seen any actual evidence to support those claims, just evidence that they had found something to do other than their job, like getting a treadmill desk at work.