If I recall correctly, there were 26 incidents involving fuel tank explosions... the vast majority involving military aircraft and JP4. On almost all, there were extenuation circumstance totally unlike the conditions on TWA-800.
The CWT on a Boeing 747 is not just a fuel tank... it is a box girder system to which the wings are attached and on which the entire fuselage is mounted. Had it "exploded" the integrity of the girder would have been vastly compromised and the wings would have come off very quickly. The reconstructed wreckage does not show such massive damage. The CWT did eventually "explode" in the disaster but it was highly unlikely it was the initiating event.
I also recall from the show, and to corroborate your account, that in the NTSB's reinactment of the explosion the foward area (forward of the wings) was shorn off and dropped to the ground like a rock while the aft area stayed in tact for a while and shot straight up, then the tank exploded. This, as you note, does not at all coincide with what would happen if the tank had in fact exploded. In that case, both wing would at the very least had been blown off, if not exploded themselves due to the extreme amount of fuel they were both likely carrying; and I do believe a CWT explosion could easily cause the wing tanks to ignite. The whole thing is just too ambiguous for me to believe the NTSB's version.