I have a .338 Win in an older McMillan Mountain Hunter Kevlar Special, stock weighs 27 ounces, so halfway between the weight of an EDGE and a standard fill fiberglass.
I would not build it that way again. Instead I would go standard fill Classic and bed it right.
McMillan will recommend magnum fill on that caliber. If you decide to go EDGE, a proper bedding job which reinforces the action area would be pretty much a necessity IMO, or it's going to give.
Awesome advice right there..