I'm not a veteran to Reo (only 3 days in, lol). That said, I also prefer a "cooler" vape. I find w/ the RM2, 28ga @ 1.2-1.3ohms is not hot at all. Well, it IS, but it is smooth and luscious; no "hot" or "harsh" going on. I haven't gotten a coil w/ 30ga to meter less than 1.8ohms (or to give a satisfactory vape for my taste). If you're aiming for ~1.0ohm, might as well get you some 28g or 27g. Just my experience with NON micro coils, those gauges should get to your target resistance.
ETA: And as others have stated already, 30ga is always a versatile size as well. We all coil differently (i.e. one person's 6/7 wrap 28ga can be the same resistance as another's 30ga 6/7 wrap).