I have written another post dealing with 366 gas checks, but having one specifically aimed at the matter is good.
Use 375 gas checks. To do so you'll have to have me make the mold, which I set up specifically for the purpose. If you send me a swaged soft lead throat slug so I can fit the rifles throats precisely with a strongly designed bullet, and if you use LBT bullet lubricant, you should have no problem getting good hunting accuracy at full power. I have many satisfied customers who have, none that haven't been able to regulate their rifles perfectly, non that I know of that is.