I would have to defer you to Hog Daddy for more detailed info on the specifics of a new rifle, he is several years and many thousands of dollars ahead of me. I do think a #4 can be accomodated nicely in a Classic, and you can tailor the barrel length to the weight of the stock if it is a given, or you can specify the fill weight within certain limitations....I think they make "light", "standard", "heavy", and "sniper" , I am probably not exactly right, but that is a general idea of the options McMillan offers. What bottom/ magazine you plan to use as well as optics also factors into the overall balance thing obviously.

I see that you already have at least one custom rifle, you probably know more about this stuff than me, I do like to talk about it though eh.....................<grin>