How do I "mic" a fEARful?
fEARfuls are designed so that they do not color your sound as much as most bass or keyboard cabs. The sound that comes out of the cab is for all intents and purposes much like what you'd get by using a high quality DI box going to the Sound Reinforcment system. So, for many players there's nothing to be gained by putting a microphone on it.
If you still feel you have to put a mic on it because of effects use or to get some "air" or because you like the coloration of a certain microphone, experienced sound engineers in live venues or in the studio will have no trouble placing and pointing a single well-chosen mic. fEARful driver elements, unlike those of many of the fEARful imitators, are very close to each other, and optimally aligned on the baffles.
For the tyro, experimentation will at first be the key. The general idea is to get fairly close for live use so that rejection of other sound sources is better, with mic placement approximately centered between the drivers and pointed to change the general balance. Aim it several ways until you hear the balance you like best, or slightly change the general position. Have fun experimenting on your own time using recorded bass parts to get a better feel for this. This is not so different than micing a saxophone or other mutliple-source instrument, so don't overthink this.