I couldn't stand the beam pattern also & wound up putting the Microstar in a solitaire powered by a AAA size Li-Ion + resistors (i think it was two 4.7 ohms in parallel - wrapped in electrical tape and small piece from a ball point pen spring). Sanded down the reflector quite a bit so the hole could accept the Microstar. The beam pattern with the sanded down solitaire reflector is not too bad - very wide beam, with lighter center spot than the 2xAAA minimag and much thinner & lighter yellow ring surround by a soft, wide + usable sidespill.
For the 2xAAA, used a AAA size Li-ion with a 15 ohm resistor in a tube and MJLED + drilled mag reflector. Not as bright as the Microstar, but nice sustained white beam. I originally tried 2 alkaline AAA's, but not as bright as the Li-Ion even with fresh alkalines and the brightness dropped off very quickly.