Recommend caliber for upper suppressor host?

[LanceS4803]

I have a new Thunderbeast 30BA for my M700, but want to also use on an AR upper platform. (My current upper has a pinned muzzlebrake on a 14.5 barrel, so don't want to remove that.)
Was thinking of just sticking with 5.56, but the 6.5/6.8 calibers have my interest now.
Will be used primarily for coyotes and possibly a deer or two.

Any recommendations for a caliber for this suppressor?

 

[FCS]

-15: 6mmAR, 6.5 Grendel, 6.8 SPC, 300 BO

-10: 6.5 Creed, 260, 7-08

If you have a -15 already, I'd take a hard look at 6mmAR, 6.5 Grendel.