50 pounds weight will likely pull the drywall down on top of you.
If you can run the beams all the way to the walls and support their weight on the wall instead of the ceiling that would work much better.
Another option would be to put expanding braces like used to hang ceiling fans inside the ceiling and use the beams to cover the holes
yet another it to cut a 2" hole and using a drill extension to drove a self drilling screw screw attach a wire to the joists either side of the hole.
The attachment of the wire to the joist could be by a two-hole angle bracket with one hole for the screw and the wire hooked through the other hole and twisted. you're going to want to use hex or square drive screws here because you're driving them one-handed.
the wire carries a coupling nut that has been drilled through for the wire, screw some all thread in there to provide a hanger point and to fix the nut in position on the wire.