Hi! I'm so sorry I missed your tag last week about the cabergoline. I've been so busy, I haven't been around much lately.
Anyway, with Floyd, we have been soooo lucky with the cabergoline. No side effects whatsoever. He started responding right away earning reductions left and right, so that was a little hairy at first. He has gone up since then but is doing incredibly well on it (when he doesn't get into the mac & cheese). He still bounces, but not usually as high or as long as before.
As far as the fructosamine, I personally do not feel it's needed in a cat who is being home-tested as much as we test our cats. I have only ever done it on Floyd once, and that was only because we got new blood machines and were testing them out. The idea behind the fructosamine is to get an "average" of the blood glucose for the previous 2-3 week period. You have even better than that with your SS!
IMO, the best way to test the response is how the cat is doing at home, in addition to your regular BGs. People look at Floyd and can't believe he's the same cat as a few months ago. He looks 5 years younger, filled out (maybe a little too much!), beautiful lush coat, grooming again, etc.
Let me know if you have other questions, I'm happy to answer! Good luck!