if you can handle the 1.5mm, i think you'll get better results than the 1.0 mm. Also because your scars are located on the cheeks (meaty area) where it can handle a more longer needle size compare to the temple, and side of the forehead where it is thinner.
I'm currently using 1.5 mm roller and dermastamp and so far it looks promising. I want to roll more frequently but it may do more damage than good to your skin. Rebuilding collagen takes a while and goes through phases, if needling is done before your new collagen is laid out in an organized fashion, you might be just wasting your time.
I'll order a 1.5 mm next month. I have heard conflicting reports on how often to roll, some saying that it's worthless to do it often, others saying it's pointless to wait so long in between. I am seeing results the way I am doing it though, so I figure I can proceed the way I am currently and it'll be safe.