Some nice circles!

I had a long list of questions for John before we started, including short beds vs. long beds in trucks (the downside is if you turn too sharp, you'll break your back window; the upside is they're easier to drive around town), auditing Lucinda (she uses a microphone to the rider, so you have to loiter near her to hear), derbies (yes, I can start them at training level), California (he is going to Twin Rivers, but it probably isn't worth it to ride novice), my life, schedule, and stalls.  John said if he is losing weight, and Body Builder helped, go ahead and put him back on it.
From there, we went to work.  Although Duke was a little tense from the wind (and maybe not getting turned out this morning), he put himself to the task pretty well.  John added a bit from the last few lessons, having me work on making him more round, and then also having more impulsion.  I had a few insights, although I'm not sure how well I'll be able to capture them, but one (that John noted) was that it's easier to bend him now because I'm not also giving up the outside hand.  I noticed I had a bit more control using one hand but not the other, which suggests that most of my riding life, when I use the right hand I am also using the left hand (and ditto for my legs).
I was also, when trying too hard, putting my outside leg too far back, which pushes his haunches in.  If I thought about keeping the outside leg up closer to the girth, it made it easier for Duke to get his body aligned on the proper track.
We worked on bending, then keeping the bend but using the outside rein for a half halt to even up his shoulders.  We also worked on a leg yield out, but keeping that half halt rein to keep him from bulging out through the outside shoulder to move away from the leg yield.  John suggested I make the checklist of aids in my head, and then check them all, since that's how I think.  So if I put on the leg yield aid, and don't get Duke lined up on the track, next check whether I used the outside aid as a half halt at the same time, or if I only used the leg aid.
We got a few very nice 10 meter circles at the trot, and our transitions were not perfect, but were lots better than they were at home by myself.  John would have me give forward when I got everything lined up, and then Duke would carry himself.  It only lasted a few steps, but John said to just make sure that after those few steps, when I feel it change, to put the aids back on.
The art here seems to be the ability to use each aid independently - each hand and each leg doing a different thing, and changing, as needed, from step to step.  It is cool that I can see that - and do it (sort of) when John is telling me each one, because that isn't even something I could have been aware of a couple years ago, but man - that is a steep hill to climb.
At one point, on a 10 meter circle, Duke had his haunches in, and John said it was good I could feel it, but why was I waiting for him to tell me to fix it.  This one we tried first to fix it with the outside half halt, which Duke ignored, so then we did a counterbend to the outside, then bent him back in without giving up the connection on the outside.
We also did a few 10 meter canter circles, which were far from perfect, but pretty cool we could do 10 meter canter circles.
The other thing is not to let my hands drag down (and forward) when I'm trying to give an aid, but make sure to carry them.
It was a great lesson; Duke is a sweet little guy and I feel like he's coming along quite nicely.  I just wish I could retain it to describe it a bit better in between the lessons.