Hi chemie,
I have been away from my build for a few weeks. Glad to see your making progress.
I would have to disagree with your assessment that an 8oz tank will pull out, that is without making some kind of mod. Mine will not pull out, no way without modifying something. I was able to use the 8oz on my sons profile plane, got lucky, a perfect fit.
I will get started again soon on my SSE. I think I have the hatch figured out, and I am not worried about any structural weakness. There have been several people that have made the hatch without any problem.
I did look into other tanks, but as I recall, there wasn't any advantage to them, so I bought the Dubro 10oz. I like the "bottom lip" in front of the Dubro. Helps with the plumbing.
I'll post a pic as soon as I can find my wife's camera.
Oh, and thanks for the PM letting me know about this thread.