I suspect that if you had a hard limit of 45 minutes after which time you could no longer work on your task, you'd adapt and find yourself able to get in the zo

I suspect that if you had a hard limit of 45 minutes after which time you could no longer work on your task, you'd adapt and find yourself able to get in the zone much more quickly. It also becomes easier the more you do it. I've been doing side projects for many years.