Paul,
If possible let's try and keep these threads separated. I can tell you what I do, and I'll preface it with nary a broken bent feather if at least a decade.
(How's that for thumbing my nose at Murphy?)

The hawk learns that the GH is a GOOD thing. I do lots of feeding in the GH with a light on. The hawk is brought to the GH with the food already in the GH. Once he or she sees the food in there, they hop right in... The door is closed with a light on inside it. After a bit the light is turned off and the hawk is in there for the count. Now then Let me back up, you can start this at any age, but it best learned in the evening so the hawk will be there for the night. I have seen my goshawks fly in and sleep in their GH,even after a couple of years not being exposed to them.
BTW my gos is riding in the truck unhooded.