I'm at the same place as you but with a 1-7.5 twist 6mm creed. Please let us know what he says, I'm very interested in this bullet.With listed optimal twist rate of 7" I may be out of luck with the factory 7.5" on the Howa.
I'll have to shoot him a message and get his thoughts on performance in the ARC with the 7.5" twist. It's definitely intriguing though.