Good for you. Sounds like pretty logical troubleshooting.
Yeah, it will likely take someone dropping the front of the belly covering to see what's going on. That's exactly what the first few pictures in my photo link show me doing. At that point I had just taken the screws out of the front and maybe 5 or 6 feet back along each side. That was all I needed to see where my leak was. To be most honest, if I wasn't so danged picky I could have left all the insulation alone, after hosing it off, and just dropped a few more feet of the belly and tried to replace my tank and just zip it right back up.
I'll be eager to hear how it goes for you. Now enjoy the Holiday weekend!