I bought a 15.1 tb 3 yo hoping he would grow a couple of inches. He didn't, so next time I bought a 16 hand 3 yo tb. He was nearly 17 hands when I sold him as a six yo because he was too big for me.
Do you need to lunge? I have one who can be tricky, he has learnt that he can straighten his body away and you cannot hold him. (With previous owner).
So we loose school if can't ride fir some reason.
If you are box resting, would it make sense to take the shoe off and poultice the hoof for a few days. We used the animalintex with 2 nappies over it, then vet wrap. So it also had some cushioning. We carried on with the nappies and vet wrap for another few days and turned out with duct tape...
I have had similar with mine. Trot sound in a straight line, lame and reluctant to trot on a circle when lame foot to the outside. Tender around seat of corn and inside heel. The farrier flattened the shoe to take the pressure off. Some improvement for a week or two, but then lame again. Tried...
Happy to share the wine 🤪
I would go with your gut instinct. If he is 90% better why risk setting back.
Can you organise the SI injections to cause the least possible stress.