Have lilja, hart, PAC nor or shilen copy your factory contour. All of them minus lilja will chamber it for you too.
Stock inletting is nothing difficult and shouldn't be avoided to get what you want.
If it was mine, I'd go with a 2B Bart, 2 or 3 rock or mullerworks, or a brux. Have it Fluted or cut back the length a bit to make it weigh what you want.
I'd go with a 10 twist for your Bullet choice and resell in mind. I would prefer a 9, but I wouldn't be shooting a 165 in a WSM.
While you're spending the cash, get it Bedded and have a good aftermarket trigger installed unless you have a brand of rifle with a nice factory trigger to adjust.
