Group lesson with two of John's other students

Today I got to ride with two of John's students in a group lesson.  It was really helpful, because I could watch them out of the corner of my eye and try to make Charlie look like their horses did.  I could also watch what their horses did, then listen to what John told them to change.  We started working on a 20 meter circle, and my main instructions were to get my heels down, to bend Charlie to the inside, and then to use outside rein to connect him. 
Then we added in a tiny vertical, but you had to make a hard left to get to it - it didn't feel like a 20 meter circle turn.  To get over it smoothly (after a couple awkward leaps where I got left behind), I figured out the trick was to make Charlie really suck up, so he could rock back onto his hind legs and kind of lift over it.  Then, John made it higher, but the same method worked.  When I tried to increase Charlie's speed around the last quarter of the circle, I couldn't suck him up enough and we'd sprawl over it again.
We did it first to the left, and then to the right.  From the right, it was much harder to get the bend right to the fence.  We'd either kind of angle it or overshoot to one side of it, so that was interesting.  But Charlie was pretty good once he figured out what was going on.
John took his grid and rebuilt it to be a vertical at about M, with six strides to another vertical at F, then a bending right turn to a vertical angled just shy of X, with a slight left bending turn back over the first vertical at M.  You started on the right lead and ended on the left lead, so that last line was hard to get the line right and to end on the left lead.  Our final round, John had me do a flying change, and after a lot of hopping around, Charlie got it.
Then we finished and John put the fences up for them, and they did the same thing, but ending with another vertical (mid-line north of X) back to the second vertical (at F).
We also looked at the 2015 rules, and John said that because they conflict (Appx 8 (?) says that you have to get your last qualifying score by the closing date of the 3 day, but Appx 3 (?) says you have to get your xc score 10 days before the xc for the event), the people putting on the show will probably use the 10 day rule (he said they used to be guidelines) because they want more people to enter the 3 day. 
I really liked riding in the group.