I went a similar way to dipper. Two years ago.
I managed to get the unit up on top of a ladder, then used long pieces of threaded rod, and spun the nuts to run the unit up. Worked from corner to corner, round and round. Hardest part was getting it up on the ladder, but that wasn't too bad.
I had another ladder to work off of.
When I got it where I wanted it (2-1/2" off the ceiling), spun up another nut to lock them, and then cut the excess rod off.
I did it in a night after work, not including the gas piping or running the wire, but including the thimble/vent and elec hookup.