How big is the inbuilt fuel tank in yours?....I have a 225ltr that will actually take closer to 240 or more,which gives me plenty of range with a very Econ friendly 250hp Suz
(Especially at Cruising speeds.)
I see you have a 200hp so yours will be even more Frugal.....on the rare occasions I want to take extra...I just strap a couple of plastic 25 litres fore and aft..,which helps balance things out too.
Something you may want to consider if you are going to put fuel in the seat pods...Ie have one each side.
I don't know what sort of Boating you do...but it Seems a lot of messing about modifieing seats just to carry a bit of extra juice...on the odd occasion..pluss you loose dry storage for other kit in the process.
I can also carry four 10 litre cans in the front consul seat,but as I say it's rarley if ever needed.
Have you done the sums on how much range you have with your Rig yet?