Picking the nits: More DFRPG questions!

[tbone]

Kind of quiet around here. Good thing I've always got annoying questions!

1) Bards and instruments: I was going ask whether I'm understanding correctly that Bard-Song requires singing or an instrument, while bardic spellcasting always requires singing. But the Adventurers write-up and Spells p7 make it pretty clear: yes, that's the case. (FYI, in case anyone else was wondering.)

So I'm changing the question to this: A musical instrument seems to have some secondary merits, like backup for Bard-Song (but not spellcasting) in case the bard's voice is out of action, and general entertainment purposes. But does a bard need a musical instrument for anything? Can he perform his main bardish activities using Singing alone, especially if its level is at least a high as Musical Instrument (as it is in the template)?

2) Affect Spirits spell: The writeup for this spell (Spells p59) discusses its effects on a target's body, on armor, and on weapons. To clarify: Does a single casting on a PC charge all of these at once? That is, they don't require separate castings, correct?

If a casting does affect a target and worn/held possessions, are there some limits (somewhere else in GURPS?) on how much stuff the spell affects? For example, if the PC holds an armful of swords, gets the Affect Spirits spell cast on him, and then hands out the swords to buddies... do the swords lose Affect Spirits power when the PC releases them?

3) Command (Spirit) spell: The cost for this spell (Spells p60) varies with the toughness of the foe. Does the caster know before casting whether the spirit is fodder, worthy, or boss? (The example of the Entrap Spirits spell suggests that the caster would find out at time of casting, and could choose to let spell fail for 1 FP instead of paying cost, if the cost would be too high.) Any known ruling on this?

Thanks!