Ok, well I was told that I couldn't go on insulin because I WOULD put on weight. Metformin never worked even in the slightest bit for me, and when gliclazide "wore out" (as in became ineffective) they wanted to put me on yet another tablet. I really had to push hard to get them to give me insulin, even though I was at the maximum dose of gliclazide and my BG levels had constantly been in double digits for over a month. In the end it was only that my kidney test came back slightly worrying that they finally relented and started me on insulin.
They also told me that I would need a huge amount of insulin, probably 60 to 80 units. It turned out I only needed 15 to 20, and that was on the "high carb" diet they were recommending (though even back then I was "cheating" and only eating about half the carbs they were recommending). Since I've found this forum and discovered what true low carb is, I've halved that already small dose and now only need 8 to 10 units, and I've lost 18 lbs!
For a type 2, the trick to weight loss on insulin is definitely to low carb and thus reduce your insulin requirements to their absolute minimum. It's a strange relationship that we type 2's have with insulin, in that it is almost like a saviour and an enemy, both at the same time. If metformin (which only increases insulin sensitivity and doesn't actually increase insulin) doesn't work, then no matter what the treatment, either tablets or injections, it's working by increasing your insulin levels (either your own insulin in the case of tablets or external insulin in the case of injections).
But many of the negative effects of having T2 (like weight gain and other poor health outcomes) are related to having too much insulin (we have too much insulin because our bodies no longer utilise it properly). Low carb, even if that requires higher fat consumption, (and it does), is really the only "circuit breaker" that I think can work to fix this unhealthy relationship.