Glad you got them working. You might want to check Agrisupply.com to see if they have a disc axle that you could shorten up and remove one of the discs blade from each side of your gang. You might then be able to put the back on again. I replaced my bearing halves very cheaply as the previous owner got a little lazy on the grease. If I remember correctly, my disc is 20x20 (5 discs, 20 inch dia). SoundGuy actually posted you could shorten the gangs up, so I looked into making it look better than just taking off one disc. I found Agrisupply sold everything to "shrink" the disc down to 16X20 for 12.00 per gang. So before you sell the back set, you might want to use them to see if you can shrink them.
If you go to
Current Buyer's Guide from Agri Supply there is a picture of how they go together.
Jerry