Re: Newbie questions
If you are going to balance her ration yourself you can buy the individual ingredients needed. If you are not comfortable balancing her ration we suggest you contact somebody on the balancer list for assistance determining what is needed to supplement your hay. https://ecir.groups.io/g/main/files/6%20Diet%20Balancing/HAY%20BALANCING-1.pdf is that list.
The timothy balance cubes are - as the name suggests - balanced to themselves and need no other supplementation other than salt, flax and Vitamin E.
As far as your vet - at the end of the day you are the one responsible for Rose and you are her advocate. If your vet doesn't agree with that perspective it might be time to look for another practitioner. I had a come to Jesus moment with my vet when my mare was 25 and could barely breath (pre-PPID diagnosis) over where we were going with her treatment at that point. As nicely as I could I pointed out that if we didn't try what I wanted I was going to have to put her down because she was suffering so what did we have to lose? She lived almost 7 more years after that.
Rose sounds like a typical IR pony plus she was a rescue so you don't know if she was starved at some point before which creates its own set of issues. You can double net the hay, use smaller hole nets and/or put a muzzle on her to slow her down. As long as you control her intake (measure the amount she's fed each day) she won't gain weight.
Swelling in the udder area can be a sign of IR or something else. Personally if it's not showing signs of heat or discharge I'd just keep an eye on it and maybe take some pictures to monitor it.
Buggzo - IMO it's overpriced and since you don't know what the grain by products used are it could be an issue. I've used straight garlic before and it's worked a treat, but you have to have a horse that will actually eat it. None of the ones I've used it on were IR or PPID so that wasn't a concern with them.
Keratex is a basically a bandaid. In order to get Rose's feet in better shape you need to make sure that she's being trimmed properly. To do that getting a full set of hoof pictures posted and sending a note with something like "Lavinia, hoof markups requested" at least a week prior to the next trim would be helpful. Directions on that: https://ecir.groups.io/g/main/files/6%20Diet%20Balancing/HAY%20BALANCING-1.pdf