Get a step-bit, D26 pill, and goggle “match mod”, and you can modernise your minimag with whatever emitter you want. 800mA boost driver works great with alkaleaks or NiMH cells and runs forever. Or get a 14100 for running with a single Li cell, and your driver of choice (within reason).
I hate those rattly tail switches, as they ruin the clean sleek design of the MM.