The female part of the ball joint with the plate is OK.
There are two male parts of the ball joint, one has a 3/4" threaded end the other 7/8".
I only have sidecar chassis clamps with a 7/8" hole, but in two chassis tube sizes, 1 1/8" & 1 1/4".
The two small two part clamps sort of fit the bike frame but I think they might need some fettling as Jon rightly says, it would be a shame to damage your frame.
It may pay you to look for some better parts but if any of this is any use to you Email me and I will find out how much the postage will cost.