I would have thought they'd be weaker. Too many cooks (or in this case, kooks).
How much stronger are two GMs working together than they are apart?

In a 30:2 match, would two GMs who have FIDE ratings of 2614 and 2736 respectively working together be all that much stronger than if they were separated? If stronger, how much stronger do you think they'd be?
I think it depends on who the players are - more specifically: how their personalities get along. If they work together really well, then they may play stronger together: even if to "blunder check" for the other player at worst. However, as @blueemu pointed out: "more is not always better" since they might get into each other's way or disagree about a core plan.
We don't really need to speculate players (GM or not) working together because we already have this! Vote chess! This is a great medium to test this: just pair two GMs together and see how they do
Also, there is a game called "brain and hand" (if I recall the name correctly) that is somewhat popular in some streams. In that game, two players (with the stronger of the two usually operating as "the brain") work together in a game against an opponent (they may or may not be playing the same brain and hand, since it might just be one opponent playing a normal chess game).
In this, the "brain" simply calls out the piece (or pawn) and the "hand" teammate must try to figure out what they are planning. Obviously, a brain and hand who know the play style of the other is an advantage in this game. Let us take move one for example: the brain side could say "Pawn" and the hand must figure out which pawn. Likely e4 or d4 based on popularity, but who knows. The point of this game is fun and teamwork, but naturally many mistakes in communication is common.
In a 30:2 match, would two GMs who have FIDE ratings of 2614 and 2736 respectively working together be all that much stronger than if they were separated? If stronger, how much stronger do you think they'd be?
I think it depends on who the players are - more specifically: how their personalities get along. If they work together really well, then they may play stronger together: even if to "blunder check" for the other player at worst. However, as @blueemu pointed out: "more is not always better" since they might get into each other's way or disagree about a core plan.
We don't really need to speculate players (GM or not) working together because we already have this! Vote chess! This is a great medium to test this: just pair two GMs together and see how they do
Also, there is a game called "brain and hand" (if I recall the name correctly) that is somewhat popular in some streams. In that game, two players (with the stronger of the two usually operating as "the brain") work together in a game against an opponent (they may or may not be playing the same brain and hand, since it might just be one opponent playing a normal chess game).
In this, the "brain" simply calls out the piece (or pawn) and the "hand" teammate must try to figure out what they are planning. Obviously, a brain and hand who know the play style of the other is an advantage in this game. Let us take move one for example: the brain side could say "Pawn" and the hand must figure out which pawn. Likely e4 or d4 based on popularity, but who knows. The point of this game is fun and teamwork, but naturally many mistakes in communication is common.
Thanks! I didn't know there was a name for it, but this is what Yasser and Eric were doing. Yasser was the brain.

...Thanks! I didn't know there was a name for it, but this is what Yasser and Eric were doing. Yasser was the brain.
Yup - that is it. I know IM @DanielRensch and some others have played this a lot too.
In a 30:2 match, would two GMs who have FIDE ratings of 2614 and 2736 respectively working together be all that much stronger than if they were separated? If stronger, how much stronger do you think they'd be?