and then once you eliminate that much to be leak free, I guess all you can do it to fill it 1-2 inches at a time and let it set till you are for sure you have no leaks, then go another 1-2 inches, wait and see etc..
I feel for you Brother, but I have spent over a week, leak detecting, to find a pencil size hole in a 75 ton fish hold 1-2 inches at a time...
Problem I had, was the smallest of wakes in the harbor would rock the boat enough for the water, that was standing on a rib, to pour off, and I thought I had isolated the level of the leak, as it dumped into the bilge...What a headache...eventually I found it, and so will you...
Keep up the good work, it comes with all the pleasant things, you've had to do so far...