A reference/link to focus training would be much appreciated. As for your experiments with getting less sleep vs better focus, I think that stuffing more hours

A reference/link to focus training would be much appreciated. As for your experiments with getting less sleep vs better focus, I think that stuffing more hours in the day is only more effective for tedious work, where you don't have to think much to get it done. In my experience, when the quality of your ideas and code matters more than just getting it done, you definitely should be well rested. In most cases, the self-inflicted pain from getting less sleep is just a psychological substitute for real productivity