I've done Dynamis many times as BLU/DNC + THF/DNC (my friend). We fight DC's for coins and +2 items. DC's tend to have weird lopsided stats. Some of them have a ridiculous amount of HP but otherwise mediocre stats, while others have normal stats except ridiculous defense (for a DC) and others have normal stats except ridiculous evasion. It's very much a YMMV deal. Otherwise BLU crush's the mobs in Dyna, spam JA procs then slaughter it with CDC. I find spells to rarely be worth it as I mostly use my MP for Dream Flower and Magic Fruit so neither me nor the thf need to waste TP on cures. One CDC -> CA + Efflux + A.spikes is enough to take a DC mob from 90% down to 20~30% which is usually followed off by a Q.Strike to finish em off. Time is very important in Dyna, I don't like wasting time casting two to three spells when I can cast one and have the same effect. HS actually works pretty well in Dyna, only things like DC crows and such have enough evasion to make landing it a PITA.