I really like the way you've organised Terra Extra. It's a lot less confusing than what you have for a lot of the HP stuff. The only downside is that it feels a bit less like I'm looking at your sketchbook, but that's a minor one in my opinion. I think it'd be great if you could eventually switch the HP art over to that format too. It's easier to use, and I got the impression you liked it more for ease of update.
I must say I love your art.