A fellow detectorist i encounter during odd 3-4 ish year intervals at a local detecting site has been running a big coil on his AT.
we've hunted together and my less than AT holds it's own ; kind of. He has me on a couple more inches of depth and I.D. maybe.
He is highly experienced for a lot of years. Aren't we all.
If he's running a bigger coil it's likely not for more challenge. (No he's not coin shooting in trash along a metal fence under some metal bleachers under a power line.)
He probably explained his reasoning but the pounded site he might want more depth in. He did say he was tying to get the most out of that model (AT Max) he could.
He still turns up an old coin now and then. He has outpaced me on those . The last one was with the AT Max.