If it's very little trash/iron, I'd go with the 11" stock. Much deeper. (Use the Target Trace magic to assist in moderate trash.)
If it's really trashy, I'd choose the 6" ML round. (The 10x5 wouldn't be in the running.)
I know it's almost sacrilege to say this...but the longer I detect, the less I like Joey coils.
To me, they're kind of the worst of both worlds, for my kind of coin hunting.
They are limited in depth by the smaller dimension, but they can still mask a good target if they get over trash and a good target simultaneously...alone the longer axis.
While they can often work better (than a large round coil) in thick trash, in my experience they typically don't work
as well as a small round coil.
I think about the only application they truly excel in, is beach work...where you're still getting decent coverage (swath, per swing) but you have the advantage of the smaller dimension (width) for sensitivity to smaller targets...like earrings, small jewelry and micro-gold.
That's my opinion based on my own testing and experience...that and $2 will buy you a cup of coffee.
Good Luck, and HH
mike
Edit:
There is an application where I do recommend joey coils for coin hunting...and it's this:
---> If you want to intentionally limit the detection depth but still get good coverage.
Either for a beginner, or if you're only interested in shallow and/or surface coins.
My wife has one on her T2 specifically for this very reason...she still gets the 'swath' coverage of a large coil, but the depth of a smaller one. (She hates to dig deeper than 5 or 6".)
I hunt for older, deeper, "iffier" signals...old coins...while she hunts for clad and shallow rings.
At the end of a typical hunt she kills me on total coin count, especially surface quarters...while I'm digging halfway to China for square nails (and the occasional old silver) LOL.