Metamagic for a Bard/Sorcerer Spy?

[Veldrenor]

Right now I'm playing a Stone Sorcerer 1/Lore Bard 4. We're about to have a time jump in the campaign that will take all of us to level 8. My character is a spy and social manipulator serving the human kingdoms in the current war against the elves, so I intend to pick up two more levels in Stone Sorcerer for Subtle Spell and Alter Self so that he'll be more effective at that job. What I'm stuck on at the moment, however, is what other metamagic option I should take. My primary role in combat is as debuff/control, with some healing on the side, so there are a number of metamagic options that I can see a use for.

Careful Spell: low SP cost, protects my allies from spells such as Faerie Fire and Hypnotic Pattern (and Fear/Confusion later on).
Extended Spell: low SP cost, makes Alter Self and Invisibility last longer and will make Aura of Vitality next level even more effective.
Heightened Spell: blows all my sorcery points, but sometimes you really need a foe to fail a saving throw.
Twinned Spell: costly, but it lets me double target with Dissonant Whispers, Phantasmal Force, Suggestion, and Heat Metal.

What option would serve me better, or am I barking up the wrong tree and should skip the two Sorcerer levels altogether (sacrificing Aura of Vitality or Counterspell for Alter Self through Magical Secrets)?

[Kane0]

I'd go with careful.

Extend would be my second choice, but it would compete with subtle for out-of-combat use and makes a select few spells shine as opposed to careful which would be handy on more especially given the role you want to cover. Fights rarely last long enough to want extending BFC spells anyway.

[bid]

Lore 6 is hard to beat. How else would you get aura of vitality?
Bard 7 adds greater invisibility.

Twin buff spells is the strongest use after subtle. If you have buff spells.

[Citan]

Right now I'm playing a Stone Sorcerer 1/Lore Bard 4. We're about to have a time jump in the campaign that will take all of us to level 8. My character is a spy and social manipulator serving the human kingdoms in the current war against the elves, so I intend to pick up two more levels in Stone Sorcerer for Subtle Spell and Alter Self so that he'll be more effective at that job. What I'm stuck on at the moment, however, is what other metamagic option I should take. My primary role in combat is as debuff/control, with some healing on the side, so there are a number of metamagic options that I can see a use for.

Careful Spell: low SP cost, protects my allies from spells such as Faerie Fire and Hypnotic Pattern (and Fear/Confusion later on).
Extended Spell: low SP cost, makes Alter Self and Invisibility last longer and will make Aura of Vitality next level even more effective.
Heightened Spell: blows all my sorcery points, but sometimes you really need a foe to fail a saving throw.
Twinned Spell: costly, but it lets me double target with Dissonant Whispers, Phantasmal Force, Suggestion, and Heat Metal.

What option would serve me better, or am I barking up the wrong tree and should skip the two Sorcerer levels altogether (sacrificing Aura of Vitality or Counterspell for Alter Self through Magical Secrets)?
Hi!
You should certainly not skip the two Sorcerer levels, unless a) nobody else in party can get Counterspell and b) you feel you can't wait two more levels.
Beyond that, I'd just take the second metamagic depending on the spells I plan to use, which in turns can depend a bit on party composition.

Like...
- You intend to pick Aura of Vitality with Magic Secrets as supposed? If you are the main healer, just that could make Extended worth enough.
- You will have fun with Hypnotic Pattern / Fear? Careful is best here (just double-check with your DM he follows RAW and not RAI, otherwise it's meh).

The two metamagic could be worth only if people count on you as the prime debuffer. Otherwise, my opinion is that they would take too much resources for their worth (you'd probably have to convert a few slots, and Bard has no recovery mechanic to compensate so you may run out quickly in tough days, or be frustrated of not being able to use it at the right time).

Yeah, I'd really pick either Careful or Extended, depending on the kind of spells I think I'll use the most often. As a Bard, both synergize with a great lot of spells (plus those you can take from Magic Secrets): making here a non-exhaustive list of those where I think the extent actually is beneficial in practice: for example, Hold Person? It's rare it lasts more than 3-4 rounds in the first place).

Careful
Faerie Fire, Thunderwave, Fear, Hypnotic Pattern, Stinking Cloud, Web, Moonbeam*, Entangle*, Confusion, Evard's Black Tentacles*, Hunger of Hagar* etc...
Obviously AOE spells too, but by RAW your allies would still take half-damage (most spells damage on a successful save) unless they have some feature of their own to reduce (Absorb Elements, Bear rage, Protection from Energy, Warding Bond) or avoid (Shield master reaction, Evasion) remaining damage.

Extended
Longstrider, Silent Image, Sleep, Unseen Servant, Enhance Ability, Heat Metal, Invisibility, Silence, Bestow Curse, See Invisibility, Suggestion, Plant Growth, Stinking Cloud, Conjure Animals*, Fly*, Slow*, Haste*, Aura of Vitality*, Walls of X*, Rope Trick*, Circle of Power*, Greater Invisibility, Polymorph, Animate Objects etc...

My suggestion would be answering this question: do you often use (or plan on using when you get it) 1 or 2 spells during encounters, that would strongly benefit from Careful metamagic?
- If yes, take it. That way you have a few predictable tactics your party can rely on.
- If no, take Extended: whatever spells you learn, you will always have one that could benefit from this metamagic on any day. :)

Especially if you plan on taking Ritual Caster feat (a few great rituals would benefit from an extended, like Comprehend Languages, Unseen Servant, Phantom Steed, Leomund's Tiny Hut, Water Breathing / Water Walk) or a Life Cleric dip somewhere.
Note also that this advice is given under the assumption you won't take any other level in Sorcerer, so you will stay with a very low pool of SP for all your life. If you had said you were instead making a "half-caster" of sorts that won't ever have more than 4th or 5th level spells, more costly metamagic could have been more interesting in the long run.