Definitely move the axles back. Again, 10% of combined boat and trailer weight should be on the tongue. As I said earlier, tire pressure is critical as well. I would not spend tons of money on tires, shocks, springs and or air bags if you do not plan on keeping the vehicle for along time. By moving the axles back you effectively accomplishing two things. You are first lengthening the wheel base and second you are adding tongue weight. Both are very important. Look at over the road tractor trailers. Their axles are as far back as they can possibly go. Not what you want to do, but just good for illustrative purposes. Anyway, I hope we have all been of some help and get you on the straight and narrow soon.