Hi Chris,
I suspect that giving up smoking has a lot to do with your BS problems. I gave up nearly 2 years ago and for several weeks my BS was all over the place. I suspect it is because your body is having to fight nicotine addiction and so is under considerable stress. Stress does play havoc with BS levels.
The glitazone family of meds are designed to reduce insulin resistance so act in a very similar way to metformin but are much more powerful. I've not heard of pio being less potent than rosi (or vice versa). As far as I am aware the only drugs that available that are designed to reduce insulin resistance are Biguanides (metformin/Glucophage) and thiazolidinediones (the glitazones).