The worst productivity idea ever is scheduling your day so you're 100% utilized.
It offers no slack for (1) opportunities that arise, (2) dealing with crises, and (3) rest/recovery/sustainability if you happen to need a bit more than usual sometime.
Do this --
Write down everything you're firmly committed to do.
Estimate how many hours it would take to do it all.
Make sure there's enough flexible slack time built into it.
(If you want to stay uber-hardcore productive, you could make a list of 10-20 things that are the only things you do with this time. But make very sure that fitness, napping, and just plain thinking are all included.)