I've had 2 laminitic horses. One who never had more than just a little discomfort and one who rotated 7 or 8 degrees on her left fore and 14 on her right fore. She had a severe onset and rotated within hours. She spent 10 days in the ICU at OSU and at one point, I had actually said to put her down. We gave her 24 more hours to get up again and she surprised us all and did.
She was never ever shod. I was always very careful of her diet but learned over time that especially mares, will have flare ups occasionally, due to hormone fluctuations. No matter how careful I was of her diet, trimming and such she would flare, spring and fall. Fall usually not as bad as spring and the vet at OSU said it had to do with her hormones. She was 16 when she foundered and 26 when I finally had to put her down. By the time I put her down, you could feel the tip of her coffin bone through her sole and it was only a matter of time. I kept expecting that the farrier would say that each time was the last when he came out.
Unfortunately, she had an accident and cut her good leg to the bone very badly and was going to have to be stalled and bear a lot of weight on her bad leg for an extended period of time, so I made the decision to let her go. I didn't think fixing the wound on her one leg and forcing the bad leg to get worse so that it would hasten the descent of the coffin bone sounded like a very good idea for an old horse.
In the beginning, we put boots and frog support pads on her and after a while we trimmed so she was comfortable. I never rode her again and never bred her again, just retired her and would turn her out in the arena with her friends so she could exercise but not graze.