Putting Ctrl in the home row by replacing the useless Caps-Lock is sufficient for me .

Alt is easily reached with the thumbs and shift is already close enough to the home row, with shift-ctrl using both pinkies.

No, this is insanity. Mod-tap has an inherent delay. Using it for anything but the most rare operations (like "shutdown") would drive me crazy. If you can't reach mod keys, unless you're arthritic or have otherwise reduced mobility, change your technique instead of doing this.

The only substitution I do is to replace Caps Lock with Super and Super with Escape, plus standard F key mappings when using a <75% and arrow key mappings on 60%.

I've never found pressing modifier keys to be an issue. I'll be mindful of my use today.

I guess the hold to repeat input (of letters) is not used much, so not a significant or noticeable loss when replaced. I'd certainly see false positives and having to type slower as deal breakers.

No but that does look interesting

It's a cool experiment, but:

Over time, the negative feedback from these misfires has trained me to type more slowly and thoughtfully, burdening my mind with uncertainty that impedes my natural typing rhythm and unconscious flow of thoughts onto the computer screen.

I get using the modifiers as a potential accessibility solution. But if you're otherwise able to type on the keyboard just fine, this is easily counterproductive.

I do have Ctrl under ä (which would be the semicolon key on US layout, I think). Interestingly, on Mac (with Karabiner) it caused regular mistypes when typing fast, even after a year. On my 12 year old Thinkpad (Linux with keyd) however, I've never found the overloading to be an issue.

I'll probably give the layout in the article a shot. It sounds interesting.

Yes, partially. I’ve used alt under the A key for about 7 years now, and ctrl under the semicolon for maybe 6. I also have ctrl under z as well.

I have - no problem doing this with qwerty also. It put me on a journey to minimal keyboards. What motivated me was eliminating unnecessary keys and reducing hand movement . Needless to say I really like it.

I have been using home row mods for about 6 months now, and followed this page to tweak timings. I adjusted pretty quickly, and while will still sometimes end up with incorrect inputs, my typing has become crisper (to avoid unwanted mods). I think the benefits outweigh the drawbacks. I really like using my middle fingers for shift.