Here's the response I got back from Mark; he tried to post it here but couldn't (I don't think he's a registered user -- YET Right, Mark? )... so I'm putting it here for him...

"Actually all of the new arms we have for this past year have been redesigned and we eliminated the 3 prong nut and use a flanged or propel nut in the main arm, we also beefed up the main arm and eliminated the breakage problems. You can literally tighten down the center adjust screw until you round out the screw head and it will not break and I can assure you can tighten it down more then enough to eliminate any hook movement. We normally trim off a little of the hook just to make loading an arrow easier, but many still prefer the longer hook and actually the curve of the hook eliminates a lot of grabbing."