Install the buckets from the link in the description of the mod, and make sure to deactivate any buckets from GEM group as they conflict.
To quote the rather sour reply that I got from the author/editor, "Read the description. U have to use different buckets." Until someone manages to find the original, unedited mod, this is going to be the best alternative we as the community have. I guess you could also try to find a roto-tilt quick-connect and try your luck with that.
I found JWeezy's Komatsu PC138 Bucket fits on it and looks a good size for it, just have to put up with it not being the same colour as the Machine but you could just make the Excavator itself yellow to match lol. also Cat 309 Excavator bucket fits on it if you want a black bucket but looks a bit small