I find it interesting that you would have problems from what was quoted "rebuilt by AWB". The holders Alan made me was as tight as any 8x10 holder I have. If you have pieces Nailed to the back it sounds like trouble as well. However, to address the idea as to what to expect, if these are converted from plate holders, perhaps this is the best that could have been done. If they were always junk, then how good can one expect junk to perform. (Sorry for the strong words there)
That is one of the issues with buying off of Ebay. If you dont have a standard to go by from specs or experience, it's hard to say what is "good" condition or not.
Personally, my holders were made (from scratch) by AWB and they are fantastic, albiet they were quite pricy.
I did this at Keith Canham's reccomendation because he told me that only Alan had asked for specs from Keith's Cameras. I've not been dissapointed.
If you would like to bring them by so I could take a look at them, I would be happy to check them out.
Best of luck,