If you like your 308 wins I don't see the reason for the 30-06. Since you are stuck on 30 cal (do you have any 7mm? That's what I would do) otherwise go magnum.
I assume you reload.... otherwise it doesn't matter on action length, mag length etc...
if going off a Rem 700 action I would not do wsm since it's too short - the SAUM was made for the Rem 700 SA. The Long action does Great, the 300wm is everywhere but I don't like the belt
. If custom go 300 PRC, or 30 nos, or go bigger 300 RUM or 300NM.
that will blow the 308 win away! And elk out to 1000yds
need more info on your potential build? I don't like adl, pain to unload. Are you going to get a new barrel? Or just Change stock? Need mag bolt