My personal experience with an EMS horse on pasture is that early stages of PPID made his EMS very difficult to manage, even after moving to a dry lot, until we started pergolide.  I would strongly advise moving your mare home.  Her May insulin was approaching a dangerous zone, and if her PPID ever gets away on you the effect on insulin could be enough to push her into laminitis even with a controlled diet.  Adding the Russian roulette of pasture to that is not advisable.  I'm sorry she shouldn't get to just be a horse on pasture, same as I am sorry my horse can't anymore either, but she can still be a horse.  If you have the time, I'd make a point of doing something with her everyday (walks, rides, training, attention/bathing/grooming), but especially getting her out of the small paddock as much as you can to explore, as that will add to her quality of life.

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Kirsten and Shaku (EMS + PPID) and Snickers (EMS) - 2019
Kitimat, BC, Canada
ECIR Group Moderator
Shaku's Case History
Shaku's Photo Album

Snickers' Case History
Snickers' Photo Album