I just went through the whole tab fitting experience and you can find more here....
An excellent addition to my boat IMHO, however I did not fit the tabs to correct any particular issues with the boat it already ran extremely well and had none of the issues that you are experiencing due to weight distribution.
I am sure the tabs will help you improve the comfort when heading into the rough stuff however I would also be looking at what can be done to improve the handling of the boat without the tabs. Perhaps more weight in the bow? are all your seats and console bonded in or could they be moved forward without a complete rebuild?
a 250 on the back of a 6.8 sounds like a lot of power and it sounds like you will not be able to use it anyway in anything but flat calm, would it be worth looking to trade the engine in for a more lightweight unit?
Do you have any pics of the boat?