'Neck -- Ah, a getting-old argument. All I can say is what I always say ... that coming up on two dozen elk, all my experiences validate all of Ed Ashby's research. You are shooting about the same bow setup as me, but lighter arrows. I can recommend at least 700 grains (Ed says 650 but that doesn't quite get it for me when things do go perfectly) with a really though 2-blade with Tanto tip. You don't want to plan for "What might work if I'm lucky?" but rather "What do I need in equipment to make certain I'm doing all I can to assure fast ethical kills even when things go wrong." And with elk, no matter our best intentions, things too often go wrong. Do NOT shoot Wolverines, which I and others have far too often had fail (bent and broken tips). The best head I've found, through long experience and experiment, so far, is the 160 STOS modified with a Tanto tip (I have no luck sharpening Grizzlies). For shooters of heavier/faster bows with heavier arrows, Eclipse makes a dynamite head. Thanks for asking, and SF (Hooray for the Crotch). d