I like the idea of the corner mount versus the midmount.
Consider this for a moment.
You could fold and carry the boom along the side piece that runs from top to bottom on your carry all. And if you had a reciever hitch female welded to the top horizontal you could position your boom there for lifting. If it's installed properly and the carryall is on the ground you should be able to lift just about anything plausible onto the carryall. Then when you're done you can remove and fold the boom and put it in it's transport position.
If your tractor is twelve volt you can pick up a pump and a cylinder from a tailgate lift off a service truck. That gives you a whole new world of opportunity for improvisation, my world, it's a good place.