I have been eighteen years on my Roadmaster project. When I first started, I too had a NOS set of ball joints but only the upper ones had the seal. I figured that if I was ever going to have new ones for the lower I was going to have to reproduce them. So after drawing them up based on the tattered remains of an old set, I came across a NOS set so that is what I used on my project. In the meantime, I finished my engineering career and bought a small farm and retired there to persue an interest in hobby farming along with '57 vintage cars and tractors. I have yet to restore a tractor even though I have a '57 Oliver Super 55 and a '57 John Deere 3010. The John Deere has an after market wide front. On the front suspension tie rods there are heavy rod ends. The rubber seals are strikingly similiar to those of the Buick ball joints. I will probably use these on my next project a '57 Buick Super two door hardtop.
I will be happy to forward a CD with the original Autocad drawings in release 14 to you. PM me with a mailing address and Merry Christmas. - Dan
P.S. I can also email the files to you if your prefer.