First, most of the advice is relating to your horse being insulin resistant and having issues with feed. Since I've read your other threads, I'm assuming this is the horse you're treating for Lyme disease.
It is of course possible that the laminitis is related to the hoof trimming and/or diet. However, it seems quite likely the laminitis might be related to the treatment for Lyme. https://equusmagazine.com/diseases/l...e_120308-10717
The latter is an important consideration, because laminitis is a rare but possible side effect of Lyme disease and treatment. "When the antibiotics are first started, the spirochetes die off in bulk," says Bushmich. "The toxins released by all those dying bacteria can cause laminitis. It only happens in less than 1 percent of horses treated, but you still must watch out for it. Feel those hooves for heat several times daily for the first few days of treatment, and if he shows any pain or lameness there, begin treatment for laminitis immediately."
If this laminitis is related to inflammation from the Lyme treatment, it could be important to treat with anti-inflammatories such as Bute for a week or two to prevent further hoof damage. I'd definitely ask your vet about this!!
Also (not meant to be offensive, at all) I would not call the laminitis subclinical because you haven't noticed it, since in the video posted it was evident the horse was lame. A horse visibly lame to the experienced eye with shoes on would not be considered subclinical, but definitely as a serious laminitis case. I'd keep in mind that the pain that is causing the horse to limp is due to damage being caused to the laminae of the hooves. This damage will affect the hooves more since he already has thin soles and a poor hoof form.
If the laminitis is due to inflammation from the Lyme, the damage could be just starting over the past few days or week, and that damage can get worse if the coffin bone has loosened in the hoof and is now sinking toward the ground. Not trying to be overly negative but you should understand that this can be extremely serious. A horse that is appearing slightly lame at the moment may be heading toward severe pain and lameness in the next week to two weeks if the condition progresses.
Sometimes that is unstoppable no matter what you do, depending on how the body responds. That's why I'd try to stop the inflammation as soon as possible. Make sure the horse does not run or stress those very fragile laminae right now.
Definitely stop any grain just in case and since you won't be able to test your hay soon enough, you can soak his ration for an hour before feeding it. Don't soak for more than an hour or the hay will lose the nutrition and he'll become malnourished. Wetting does not remove the sugars, the hay needs to be submerged and then drained after an hour. Many people use large tupperware tubs or buckets. Make sure your dry lot is not large enough for your horse to run around but only walk.
Edit: Sole pressure on soft ground can be extremely important to keep the coffin bone from sinking. If the horse is still peripherally loaded with shoes and long hoof walls, I'd get the shoes off and a trim ASAP. It could save the hooves from having as much damage, and also you will be able to assess better the pain level that the horse has. If the horse is very sore on soft ground or bedding with no shoes on, that is his actual pain level from the laminitis.