I haven't built a Langstroth long hive yet, I do have Langstroth 10 frame deep, medium and shallow supers. It would be better if I only ran one size but I use deeps for brood and med and shallow for honey. I also have a TBH, this year I did put a super on it and tried a dozen jars with a small piece of cone stuck in the bottom/top when on hive. They did work the super, not so much on the jars.
As for the weight of the Lang supers part of the time I care supers to exchange with the full ones when collecting honey and a dolly. You can put on a new super or check the frames to see if they are completely capped and swap out the frames with new ones and put the full frame in the super on the dolly. That way you are only lifting a frame at a time also. Some of my shallow supers I will have 8 or 9 frames in the 10 frame super, they will have a good bit of honey.
Good luck to you all,