How is this calculated? Is it based on the number of adjacent slots between the two crusaders, the sum of the difference in their column and row, or what?

___1__2__3__4
A__O
B_____O
C__O_____O
D_____O_____O
E__O_____O
F_____O
G__O

Assuming the above is a representation of the act 1 triangle formation, then if Cindy was in D2, then the crusaders in the circle around her (B2, C1, C3, E2, E3, F2) would get x1 whatever her buff is (based on the gear you have, this will change). So if the base buff is, say, 30%, those in a circle around her will get a 30% buff. A1, D4, and G1 would get the buffx2, meaning they would each get 60%.

If Cindy was in D4, then the entire 3 column would get 30%, the entire 2 column would get 60%, and the entire 1 column would get 90%, as each column's crusaders would be equally distant from her in their own column.

Essentially, in an ideal formation, your DPSer (or DPSers) would be as far away from Cindy as possible to receive the maximum bonus.

I should probably also mention that when calculating distance, D4 and D2 are NOT considered next to eachother. It would be counted as going from D4, to either C3 or E3, and then D3. When the formation is slanted like that, the "spaces" are slanted as well, meaning movement has to follow that pattern, as opposed to a "squared" formation, like in some events.

Does that make sense?