Lyndsey, I'm sure someone better able will be along soon (perhaps put the vid on as a new topic??) but in the meantime I'll say what I see.
Thanks for the suggestion...I maybe will do that...I'm still getting a bit lost in this forum...

...and sometimes I forget which thread I was having a conversation on...

It's difficult because I'm not wholly familiar with the Marijke way but for me it started to work for you when you moved the shoulders
and quarters (around 1.30 ish I think) and up to that point I was thinking 'move the shoulders a little' and then you did

So when I got him to move a bit more laterally...??
I'm not sure of the benefits of this work just keeping going on a circle but I can see the benefits long term of it as a part of your work. In fact at times he looked a little peeved but I know you edited down from a much longer session and so you may have worked other things into the session. For me I'd play a little with more of a shoulder-in angle so that the inside hind is 'connecting' more on a line with the outside fore and then take this into the stretching out and stepping under of the Marijke work. I think I'd also use some reinback (with a lowered head) between this and some giravolta (all of which you may well be doing

)
I'm not sure either...

...I just feel like this is the least harmful way to mess him up...

He looks peeved pretty much 100% of the time I work him!!! The only time he is not peeved is when we are playing some game where he is at liberty and it involves games like standing in his bucket or getting groomed on his belly. In other words, if he has to work, even at the walk, he's peeved!!! He has been since he was 1 year old. For me it's been his major symptom! The silly thing is that he shows up for work! So if I just stand in the ring he will come running and follow me everywhere. But if I want to attach a line to him and control his movement, back go the ears!! Charming boy!!
Anyway, the stuff I edited out was feeding treats after a release and standing around rubbing his belly - sort of changing the subject and resting - even more boring than the work (if you can imagine!!

) I didn't do rein back or giravolta in this session but I do a little of that sometimes.
Thanks for the thoughts about the shoulder-in...I think you may mean more straight line work down the wall so I can keep the SI angle...?? He is starting to do that quite well and I should maybe be mixing it in more regularly. This is where it would be nice to get to a MdJ clinic so I could get an idea of what this horse needs at this point...

Thanks Trudi!