I also bought the HF quick hitch and I like the idea but the hook does not extend out from the frame enough for my stuff either, the attachments at the top hit the frame of the QH before they are in enough to get hooked, the hook should have been made a bit longer, ( font to back ) so that it extends out from the frame more, I contacted HF and they have no adapters etc.
I'm not sure if I have enough room on it's frame to trim some off or not, I need to trim off some of the front of the frame but leave enough for the bolt holes.