You might want to look at our own Mike Brooks' kits for fowlers. Mike happens to love the 16 gauge, and while his gun is a fowler, rather than a fusil, the guns share many things in common. Years ago, My brother and I searched for a fusil or fowler that would be LHed. We were frustrated at every turn. In 2004, Pete went looking again, and gave up all together on finding a fusil. Instead, he contacted a gunmaker I know personally, to build a fowler for him. Without my knowledge he decided to have two fowlers built, and gave me the other one. These are in 20 gauge, another fine gauge. Our gunmaker made these "American Fowlers" borrowing design elements from British, French, & German/Belgian, and a bit of American influence on the lines of the stocks.
He chose to put 30" barrels on the guns. I would have preferred 36", but I have to admit that the 30" barrel shoots well on my gun, both with shot, and RB loads.
You obviously don't have the RH/LH problem we have, so you have a wider choice of guns from which to pick. However, for field work, the world does rise or fall if you use a French style fusil, or an English or American style fowler. :hmm: :hmm: :hatsoff: