I was actually more concerned that his tank was too big, not that it didn't provide enough space.
I also breed and raise ball pythons. I've never had consistent feeds when moving a snake right before feeding. It sounds like you've made up your mind about feeding in a separate enclosure and don't want anyone to suggest feeding in the enclosure.
However, you have asked for tricks to feedings, and that would be my suggestion. Feed him in his enclosure. In addition to feeding over 20K live prey with no injuries, I've also fed over 20K feedings in their own enclosures, and I've only been mistaken for food when I've not washed after handling rodents. Otherwise, the "literature" with the ample arguments are bunk in my personal experiences.
Good luck - hope you figure it out!