Lots of good responses here and I'd echo them and add a bit.
Plan switch location and order by phase of flight - from left to right I have my masters (Batt/Alt, Avionics, AutoPilot), my lights, pitot heat, boost pump, flaps.
USB charger ports, if you have to put them on your panel, put them low or you are fighting cables crossing things you want to see.
It's been a while since I installed my map box, but mine sits lower by a fair amount. I remember the plans were pretty specific about where the box fit into the panel, but that might just be side-to-side.
I think you'll regret having the cable controlled cabin heat that high on the panel, mostly for routing the cable in the sub panel area and it interfering with the many things that will get installed back there.
I built my panel as day/night VFR, as it appears you have planned. When it came time to equipping for IFR - which I am doing right now - I had to rethink the radio stack and move things around. In your case, if you can, find a way to take your autopilot panel out of the radio stack and leave room for an IFR navigator, second COMM and/or audio panel in the future. I don't know if Garmin offers a vertical model, my Dynon panel does and that works well.
I don't see any circuit breakers, are you planning to use an ECB like a VP-X? Careful, that's a hot topic around here.
Not a bad start at all. Panel planning is the one place where what you decide affects the flying experience more than most anything else. Be sure to think about the space behind the panel too, and the space behind the sub panel.