My dad put in a hot water heating system in his house. Once the proper flow rate was established on two circulating pumps , the best temp setting on the gas boiler was found and an expansion tank was added, it works well. Definitely the longest running type system. If you get good quality...
Sounds like two young guys, and plenty of supervision if you want the top of the tubes all level with each other. One of those laser leveling devices would probably be worth having.
500 pounds is easy. A few 2x4s will get you up one step. I would lay it on its side and slide it up the step. If the floor is smooth, slide it on a piece of thick carpet. If it is a carpet floor, I would slide it on plywood or 2x4s. I have move a few for myself. When they get over 750 pounds...
If I were 18 again and had a truck that would carry 2000 pounds of sand I would be all in for 200 plus gas money. But sadly for me and the pool builder those days are behind me.