The issue with jugs, is the weather "COULD BE" too rough to fill, hence wanting a bigger tank, or a bigger tank would be nice. BUT, I do race my boat, local rules require a minimum of 6 hrs of fuel
at hull speed or 80% or some such thing. As such, I do have enough fuel
. I have on many occasions ran for 10-12 hrs, have to fill in the middle with a can, not fun per say, but doable. Hauling them for the couple of times a year is not a really big deal overall here in the salish sea. Then again, the longest stretch I need to go before finding a fuel
dock is probably 3-5 hrs, well with in a tank range with what I have. I also do not like the idea of storing the cans on deck with bungies etc, so if you have a cockpit locker as I do, they do work.
Then again, going from 7-15 gals or so in my case, is not a large amount of weight. Your case, it could be for the amounts you appear to need etc.
Also the % reserve which both mdi and I referred too, that is a number you need to decide the % you think you need. 10-20 for where I currently sail is plenty, I could see in some parts of the world wanting 50 to even 100%. reality is, somewhere between 10 and 30% should be ample for a high majority of us. How it is stored could be the the issue, ie all in an actual tank, or tank and portable. Both as stated have plus's and minus's. The formula should work no matter the reserve % you want.
I was reading in the march or february issue of Sail a dream boat by a delivery skipper, his choice was a minimum of 200 miles of diesel, for his dream boat, that would be about 200 gals. THen again, the boat was in the 50' range, some of the fuel
could be also for heating of the cabins, cooking too. That also needs to be included in your tankage needs too, if you have a diesel stove
or heat, assuming the boat is a diesel not gas.
make sure you take in ALL uses of the fuel you will have on board for a tank(s) and the total amount.