Best coil for Cache hunting with MXT?

[BamaBill]

I know that people have said that the 12" coil is about the largest you can use and still find coin size targets, but what if you were cache hunting, for larger targets, what coil would give you the most depth on larger targets?

[cyeager]

And then there was Big Foot... A big 2x4 about 16 inches long... A real nice tool unless....
Mineralization.. Then DD coils are the bomb... Bigger better? Or is it noisy?

Psst. 6x10 DD makes the rounds in the worst conditions fairly reliable. Small but easy to lug.
If you need depth go big.