I would think that a front/rear wing balance point that is further from the mast would make a less stable ride. It is my understanding that the MHL Lift is difficult to ride because the balance point is so far forward.
http://www.kiteforum.com/viewtopic.phpf ... ft#p819936
The other thing that makes a wing difficult to ride is the position of front and rear foot. i.) Once a front foot goes farther forward than where a balance position of riding on the water, you'll get nose dives (pearls).
ii.) And if the rear foot is too far back, the wing is more likely to become unstable and buck.
The other variable is the balance of the front and rear wing angle of attack. Once you find a good position for your front boot (based on i.), you can adjust the angle of attack of the rear wing relative to the front, to move the balance position of where your rear foot would lie, when everything is in balance.
For example, shimming the nose of the rear wing down, will bring the nose of the board up, meaning you'll have to move your rear foot forward to compensate. And shimming the nose of the rear wing up, will bring the nose of the board down, meaning you'll have to move your rear foot back to compensate.
When I first learned to ride on my 2002 Rush Randle board, the board was unstable until I found the proper position for my front strap. After that, I used a dime to shim my rear wing. I recommend riding without a rear foot strap.