People howl like sled dogs when I say this, but you need to be in the bow and your wife in the stern. Our situation is much the same with 325 and 190 lb partners. I put a thwart about 14 inches in front of the yoke and ran a pretty long bow slider from there. The 325er paddles from there. I moved the stern seat back as far as my butt would fit, raising it up to get that extra width.
Paddling the boat with no gear the bow slider is all the way back. As we add packs they go as far back as is comfortable for the stern paddlers legs and the bow seat can move forward.
Having the heaviest person closer to the center of the boat makes a huge difference in stability in rough waters. The heavier paddler usually has longer arms and deals with the the wider paddling station pretty well. My heavy-duty bow paddler uses a 54 inch 8 degree bent with great power from a station amazing close to the center of the boat.
Moving the stern seat forward makes the stern paddler reach out to start a stroke where the hull is way wider. It also causes you to lose good leverage for steering. This really does not work well. The bow paddler moved way back works a little better as the hull is narrower in front of them. As a matter of physics, there is no way you could move the light-weight bow paddler far enough forward to balance out a heavy-weight in the stern, even with her legs hanging over the bow.
If your wife is half your weight she needs to be twice as far from the center of the hull to balance you out. Figure out how far back she can comfortably fit in the stern and move the seat there. Measure from the front edge of repositioned stern seat to the yoke centerline. The front edge of the bow seat will need to be half that distance from the centerline of the yoke minus 2 inches for good trim