Floor plan for my new boat

I just bought a 1975 lowe jon boat and i need to replace the wood floor that is in it but im not sure really what to do? it already has good wood in the front part with a chair and a trolling motor mounted to it, so i just want to take off the back wood and replace it but theres a empty spot in the middle that i would like to put another chair so that i can use it for fishing and it would be easy to put my duck blind on and the person whos sitting in that chair can see. if you have any ideas please help me!!!

 

Of course, everyone knows the '74 and '76 models like they were built yesterday but could you refresh our memory on that rare '75 with a pic or two?

 

What level do you want the middle seat? Right now, I don't have any ideas but give more info and I, or someone might...

 

i would like the middle to be above the bottom but not at the same level as the back and the front and i just took off the back wood and the seat and im going to put new floors in but im not quite sure what i should use marine grade ply wood or any thing else if you have any ideas please let me know