I've been thinking about this thread and what I might add. I'm not sure if my gos qualifies as an adult imprint yet, she's last years hatch. I have now taken her through a short tame hack, first hunting season, moult, and now preparing for our second season.
Before taking on an imprint I looked long and hard at my commitment level to this. It's not an on-again, off-again kind of relationship. At the very least you are essentially stuck with a bird for many years and at best, well that's easy to see.
Managing my bird as an adult is time-consuming, she demands daily time and affection as well as feeding and housing. But it's worth it, just be sure it's something you are committed to and your life will build around your hawk and her needs.