Fixing crack on 330g some advice

[Zylumn]

I purchased the 330g tank from Nate(great guys BTW) that was dropped. 84x30x30 When I got it home I found it to be in far better shape than I could have hoped. I was told it would probably need front and back glass and I purchased it with that expectation.
--Front glass---
There is some chips off the front bottom piece of glass but it will not affect the glass integrity as it is not cracked and an additional 3" wide by 1/2" was put in all away around the bottom inside of the tank. I understand why Nate would consider it replaced as it is not perfect and in my case I want it in a in-wall and it will not be seen. That said: I saved replacing front glass ($300) and huge hours of labor.
--Back Glass--
This one received some damage but I think I can fix it without replacing the back panel of glass. The crack is contained in a circular fashion in the left rear overflow. Now the key points here is the side and the bottom pieces of glass received 0 damage and the crack has circled in on itself with no potential lines shooting out to the rest of the back panel. Now as it is contained within the overflow there should be less pressure on that crack. I plan to add a piece of glass (the width of the inside overflow, 1/2" thick) with silicone on the bottom, side,back, and overflow piece of glass. Effectively concealing, and taking all pressure off the crack. This would save me $300 and 50, 60 hours of labor.

Heres a pic
http://s168.photobucket.com/albums/u...ked-corner.jpg

I am interested in experienced criticism and advice. Thanks for looking.

Kevin