Hey guys, after a few trial and errors, I may have found a fix for the fill hole/screw leak issue.
Will I couldn't find an O-Ring small enough to fit right so off to the hardware store we go. What I found that's been working for me so far is getting a pack of "Heat Shrink" tubes, 3/32"-3/64 is what you should get. I then cut a piece about 1.5mm - 2mm long. It will be a snug fit but it will fit. Manuver it all the way up to the treads and your done. No need to add heat on this setup. I also pickup a 3/16"-3/32" just in case and if you want to use that you may need some heat to shrink it down to size.
I still have no camera near by but I'll post some pics soon. Try it out. I haven't had a leak from that area since I add the heat shrink tube...for me it work out great and I hope it will help you too.
Jam