Chapter VII boss fight:
Equip lightning Durgas to your fists, and the Gaze of Despair and Selene's Light accessories.
Start fight. Punch, punch, punch, punch, punch, punch, etc., ... profit. You should be able to manage 1.5 million or so with every fight (which shouldn't last you more than 6 minutes).
Chapter II boss fight:
Before entering the cathedral to fight the dragon head, equip the Bracelet of Time and Gaze of Despair accessories. For weapons, have Set A with something weak on your fists (such as the Scarborough Fair guns), and lightning Durgas on your feet. For Set B, equip something like the Shuraba in your hands, and the Lt. Kilgore guns on your feet. Go in with max magic (preferably, all 24 orbs full), run up to the dragon's head, and hold down the button that activates the Bracelet of Time's Witch Time effect. Keep that held for the entire fight.
Then, while on Set A, initiate the Punch, Punch, Punch, Punch, (rapid tap) Kick combo and as soon as the lightning Durga Chun-Li style kicks start, tap the button to switch to Set B. Instead of regular lightning kicks, you'll get a barrage of rockets from the Lt. Kilgores equipped to your feet in Set B. It'll rack up HUGE combo points and multipliers. Once it's done, quickly switch back to Set A, and restart the PPP (tap) K combo and switch to Set B once the kicks initiate.
With a near constant barrage of linked rockets (thanks to the Witch Time), you'll quickly amass a 9999 x9.9 scoring rhythm, and by the time you finish the fight (don't whiff the QTE at the end of the fight), you should walk out of chapter ii with 7-15 million halos per run (each run taking about 10-15 minutes). This one's a bit tougher to do, but once you practice it a few times, it's WAY more efficient than the easier to do chapter VII exploit.