Have you seen this post yet?:
Information for Aussie Feline Diabetic Caregivers
About 3/4 of the way down is a section for caregivers with acro cats and testing. It mentions Dr. Kenny in Sidney who has done the pituitary removal surgery (he learned from the folks at the Royal Vet Clinic in the UK). If nothing else, your vet may wish to consult with him.
We had quite a few cats here on cabergoline, in fact 4 of them that have gone off of insulin completely. The main benefits are a reduction in insulin dose needed, and most important, reducing some of the acro side effects. I have never heard of anyone using pasireotide, except under the research study originally done at RVC, where the manufacturer donated the drug. It is prohibitively expensive. And there are cheaper options.
My cat had stereotactic radiation therapy. Back in the day, that was the only other option other than just keeping controlled with insulin. SRT did help her get down to really tiny doses and reduced the acro side effects for a number of years. We still see a few people getting SRT done. It's cheaper and safer for the cat than the surgery.