If my 727 shifts too soon, and too soft, which way do I adjust?

By chance did you switch your carb and/or manifold to non-standard unit as well, like a high rise maybe? I was never able to get it to shift properly when I switched mine. It changes the geometry of the bell crank and shaft movement. Finally switched to a 727 Lokar cable shift down and that solved the problem. Was less than $100 and has worked flawlessly ever since.