Just to follow up I did get some Nitro 9x10. I haven't tried the Sumtoy .375. I did order a Comp-N-Choke .370 that's what we are using this season until I can get more testing done.
However I wish I would have just stayed with the factory Mod barrel. I've seen another gun same model pattern really well with Apex. Just a heads up.
I will post an update later.