Welcome to the list. I hope you find it as informative and supportive as the rest of us do. It sounds like you're doing a lot to keep Tamera comfortable! Thermo-regulation is difficult for many Cushingoid horses so anything you can do to help is great.
What information was used to diagnose her Cushings? Is it based only on clinical symptoms or was some blood work done? If you want to find out more about how others on this list are treating their horses you can look up some of the old posts in the archives. I believe there are also some links to some very good articles there. I also found that using the search engine www.google.com and doing a search on Equine Cushings gave me some good articles on the subject. Most of the other search engines are too general and it would take a lifetime to sort through the stuff.
If you're unsure about whether to treat with meds or not you might ask your vet why he/she didn't think she needed to be on med. Sometimes they seem to postpone starting because of the expense of the drugs. This list has some sources that are quite often much less than the local pharmacy or vet clinic can compete with. If you really want to try I would press your vet a little more. Also, some people have had success with much lower doses than previously used (which reduces the cost). Again there is a lot more information out there. Its worth researching.
In the end, we all have to be responsible for our own horses. We all wish we could keep them going forever but there's only so much we can do.
Good luck and please share any information you find with the list!