Wonderful jump lesson & Duke's personality

Duke started out really obedient in the warm up, and so John didn't have to spend as much time on the individual aids.  We worked 10 meter and 20 meter circles at trot and canter both directions, with Duke needing a bit more bend, haunches in, and a bit more forward.  He felt soft and pliable, and very responsive.  I wonder if it has something to do with him staying in today instead of going out?
Then we jumped a cross rail, which John turned into a small vertical after a few times.  John's main instruction here was to keep the rhythm, not to let Duke speed up the last couple steps.  Our first two times through, we veered to the right (inside) pretty hard when we landed, but once I realized it was happening, I focused on a particular spot on the wall and that helped us stay (more) on course on a straight line.
Miraculously, we managed to get our leads both directions!
From there we started a grid that John had set up.  It was trot in, over a ground pole, cross rail, over a ground rail with a chute on the far side (ground pole chute), vertical, to what became an oxer.  John built it up as we went through it, and I took turns landing each direction (right-left-right-left).  It was MUCH harder to make the turn to the right afterwards than to the left.
Duke stayed a steady eddy as John built it up; I never really felt him bat an eye, and even when John ended it with a very respectable oxer, Duke just cruised through it.  Maybe about half way through John leaned a pole on the left side of the oxer, which I think helped keep Duke from drifting left.
For this, my instructions were to sit up, chest forward, heels down, look ahead through my turn, wait for it, and then give a bit of a squeeze just before the vertical and just before the oxer.  Then, when we landed, sit up, stay up, and transition him back down to the trot.
John said we need to work on landing, but he also wanted to check Duke's disposition when he raised the fence height, since Duke hasn't done a lot of work over big fences.  He was (pleasantly) surprised (if I dare say so) that Duke didn't use the height as an excuse to rush.
To work on landing, I tried to think sit up as we went over the oxer, and then not bend over when we made the turn.  Then we'd circle (sometimes getting him on the correct lead) and get him bent again before transitioning back down to trot.  It does need some work, and it will be hard to string fences together at the show without it, but good lord, Duke is SO much better than when he got here in June and we tore around with me ripping on his face the whole time!  I was so pleased with how well he did today, especially because I was beginning to feel like we were at one of those plateaus where John is just repeating himself and repeating himself and I go home and try to work on it but am just not getting it.  This felt like the last few lessons sunk in and we were able to show that we made some progress in between.
John also said - now that we've both been able to watch Duke and John's been able to ride him a few times - that Duke is going to be the sort of horse that I have to be patient and calm with.  I'm not going to be able to strong arm him into doing something he doesn't want to do, but if I ask him just a little, just a little more, wait a bit, ask just a little more, Duke will be doing it without even really realizing it.  John said he's a nice mover, but he's tense, and the one thing we can't do is make a horse relax.  I think he's still young, and I'm sure it's hard to be ridden by me and understand what I want, so I bet after we are a team for a few years, we'll be much better together.
The lesson made what was turning into a total wreck of a week turn around.  As much as I miss Charlie, and I miss him every damn day, I feel really lucky to have found Duke.  He's a good little guy.