Tacticians become brilliant when their opponents are all flanked and no one on your side is flanked. This is easiest achieved when you play solo or with small parties, of one or two companions. Psyblade or battlemage are probably the best MC, since both wizards and ciphers have powers (chill fog/curse of blackened sight and eyestrike/phantom foes) that will flank enemies. A tactician/soul blade MC would be a fine combination. Brilliant periodically restores class resources, including fighter discipline, wizard spells, and cipher focus. But it's much better for wizards, who get back a spell at a random level, while ciphers only get a measly +10 focus per tic. Invisibility works a bit buggy with brilliant tactician. If I recall correctly, turning invisible will trigger brilliant tactician, which sounds nice, but often battle ends as well, which is not so great, since you'll lose whatever buffs you had (including brilliant) without your resources being restored. Personally, I prefer playing tacticians either solo or with a small party. Playing a party, say, of three tacticians can be fun.