to start, I'd agree with the above and get a different boat. you are talking serious structural modification here. and on a boat that is painted over the glass.... it going to be tough.

that said you know your limitations better than I do.

I wouldn't change the center hump it's where I always fought my fish from in everything but horrible weather. when the fish was ready to net I went down to the side it was on and netted it. and I always hated the center console... except when going to and from the fishing grounds so if you put one in keep it short. they make a canvas top for the front... or I've seen them out there, that is lighter than adding a deck. less work also. but anything you put in the v's on either side of center will get wet. no matter what you do. so that's no place for storage. you could add some raised blocks to the front and the canvas and use the top of the deck as temp. storage.

as for downriggers, metal plates added to the back of the boat are the best method but two in that width is begging for tangles. there was a guy I saw that had his mounted to slide outs about 3 feet on boards so they hung over the water... but it made the boat less stable when only one was down.

thats my 2 cents... stay safe