Thanks, they pulled the mid deck board and lifted the rear seats a few inches and got it out. The main reason to pull it is when its 16 years in a 15 year tank, and it leaks, gas all out, water in. They found both in the tank. Leaking half a tank out was the giveaway originally. Merrit Marine and Carl are super nice and answered questions by email also! They are the Triumph gurus!
For reference sake in case anyone ever needs the info, on the 2004 191FS, it appears to be a standard Moeller style 40 gal belly tank, as seen in the attached pics. It can be accessed without removing the console or the the motor or the splash well. Just the mid deck plate and a little leverage up on the rear bench loosened up to have arm access to the fittings.