Challenged by simplicity

Today's weather was sunshine with intermittent holy fury of god rainstorms. We tacked up in the rainstorm. Got inside and watched the rider before us finishing in sunshine. Started riding in rainstorm. Had to strain to hear John in rainstorm. Then, once tired and wanting excuse of couldn't hear, sunshine. Then cooled off in rainstorm. You get the drift. Now that fall is upon us, I had my first inside John lesson. He had a very simple set-up - a single white vertical and then a 2 stride combination, vertical to vertical, but with flowers and colorful rails. First he gave me some pointers on the same posture issues that I've been working on with Shannon and that Major Beale identified. For my clamped right knee, which he says comes from too tight quad, open the knee. I was shocked, and then looked at my left knee and saw it looked the same. Rolling the knee open means the quad can't overpower the rest of my leg, and it, somewhat unexpectedly, puts the front of my calf on Charlie as my aid instead of the back. Then for the arched back, he said for dressage, think of something poking a finger right in between your shoulder blades, and you want to grab it with your shoulder blades. For the lower back, think about a flat palm against your shoulder blades and pushing into it, and also lengthening the rib cage up - like making more space between your hip and the bottom of your rib cage, but also elevating the whole rib cage, like a balloon is tied to it. Then, after you get used to those feelings, you undo them just a bit - so your knee doesn't really fly out a mile above the saddle. We did a bit of warm up, and I had a hard time keeping Charlie together instead of strung out. I think we were both tired from the clinic. Then we jumped the white fence as a cross rail, vertical, bigger vertical, much bigger vertical. My main instruction was to sit up around the corner, half halt at the corner, and then, infuriatingly, every single time I went to the left (we were riding a clockwise circle) when I landed. John put down a rail which helped a bit. I needed to use my left hand and my right leg - Charlie was coming in crooked (the same crooked from Major Beale's clinic, his haunches in, so bulging out through his left shoulder - off my right leg in other words), and I'd try to straighten him which would push us further left (instead of pushing with my left leg to straighten him into the center of the fence, I'd push with my right and get us even further towards the standard). This tiny little simple thing eluded me, and the elusiveness chased me to the next exercise on the combination. Here, we did it both directions, and for the life of me, I could not ride the damn thing straight, even though it was only two strides in between. Eventually, John had me halt afterwards, side pass to the right (off the left leg) and then turn left and go again. Shannon also said we tended to chip the first fence, so even though I was counting, I was coming in funny. John pointed out that I might be able to scoot through a double, but a triple, as I drift to the left each fence, is going to make us off on the strides and really hard for Charlie to bunch up and go over it. So the key take-away for this week's triple combination? STRAIGHTNESS! I was feeling sorry for myself and how pitiful a rider I was, but then I looked at the dressage pyramid and was pleased to see that straightness at least was not the very bottom of the pyramid. Charlie jumps like a champ though. The fences weren't really that big (I checked when we walked past cooling off - they were just BN), but he was really rounding up over them.