Most of the Smaller tornado's either have a tank in the console and the battery in front of it - not an option I like
Or the battery etc in the console and the 22l tank strapped infront of the console.
On your size of boat, this I think are your only real options, having such a large tank at the stern is going to make a joke out of your boat trim unless you have a simmilar amount of ballast forward to counter act the fuel.
Unless its an older boat or you have the skills and time as other forum members such a JW or Tue (photo's of their converstions in the gallery), cutting the deck out an retro fitting an in hull tank is a job not for the faint hearted.
And just because no one answers you in a day no need to get upset