.A prop with wide angle yokes simply has a single joint, but with wider yokes that can go to larger angles before binding. It'll handle more axle travel without damage, but won't help with vibration.
A double cardan joint is more or less two UJs in one unit. It's arranged that the joints are always at the same angle, and so immediately allows twice the angle that either of the joints on it's own could do. But, because the two joints are always at the same angle, the only bit subject to angular vibration is the shared central part - the rotational variations should cancel out, and it should act as a CV joint. I've seen them used (exposed) in the front hubs of 4WD tractors, and I think they are used on some Land Rovers (Disco II front axle ?).and with the 37s the last thing I want is more standard ujs..standard ujs are around £4 each the wide angles I have are £32 each..