My main is a bard too...

My song strategy has been this.... and i could be right or wrong

Priority to Ballad..... especially in 8 man set ups.... based solely on the WHM's MP.... Sch's/Smn's seem to have good MP rationing.... and BLM can recover their own MP in umbral ICE..... WHM's seem to have the biggest burn of MP... hence I watch their meters like religion.... If the WHM is ressurrected (ballad goes up).... If a WHM needs to raise some one (Ballad goes up).... If WHM is at 50% mp and the fight is no where near over (Ballad goes up)

Foe Requeim i only use in 8 man encounters with at least 2 DPS mages.... i'll sacrifice my damage to assist the MP burns of the BLM or SMN

Army's Paeon..... if we are in a heavy melee set up, 8 man or higher...... and typically they dont start running out of regenerated TP until about halfway through the fight... I'll put paeon up for 20 seconds or so, just to give em a boost...

I use Paeon in AOE pulls for 4 man dungeons if i have a DRG in party, that way they can Doom Spike, and Ring of Thorn tonberries and such endlessly..... sorry a good geared DRG can dish out 300 damage per AOE compared to my 300 or so with quick nock/RoD/wide volley when all CD's are burnt at once (im ilvl 84 with my zenith bow too)

Ive also been using alot of Paeon in Crystal Tower with Melee heavy groups