If HM2 were to cut it, (whatever is finally decided on) and if the buy was run as a choice of either a .279/280 or .286/.287 or so, I would think that it would go a long way toward getting it cut.
As far as how heavy to make it, there seem to be a myriad of good reasons that the "Target" weights seem to run 125-130 grains, and the "Hunting" weights hover around 140-150. I have no real experience loading the .270, but don't most designs begin to hang below the neck once you begin to exceed about 150grains?