UPDATE:
Been on forums of all kinds for years and I always hated when people would post a thread with a problem, get different types of advice but they never reply back to let others know what the resolution was. I didn't want to be one of those, lol!!!!! After months of waiting I finally got the tank up on the stand and I was able to install the bulkheads. I followed the advice given about sealing the weir slots and then filling the space between the inner and outer with a vinegar water solution. I used the Gorilla waterproof patch and seal tape, very impressed with this stuff. Probably a good thing to have on hand if a seam ever started to leak. After the tape was applied I filled the area with about a 70/30 vinegar/water solution and let it sit over night. Right away it began foaming at the top and puking out all sorts of crap. This morning not a drop of the solution was anywhere except where I put it. It literally dissolved all those hard deposits in a 12 hour period. What was left was thousands of small brown paper like pieces. I took a flat piece of sheet metal and 1 1/2 wide and taped a shop towel on the end and ran it up and down between the two walls just to make sure it was really ready to flush. I then rigged up a 3/8 hose attached to my homemade Python system and flushed this area out with very hot water. This forced out all the residue that was left and after doing this 6 to 8 times I am very happy to say the overflows look brand new.
Thank you all for your help and advice, it is much appreciated and I hope to be able to return the favor. Tomorrow I will get the other overflow done and I can start installing the Universal Rocks background. Thanks again and God Bless.
NCH