You might want to post some pics of what you were trying to explain. Are you saying that you do not pull the boat all the way up to the winch post? I think you are leaving yourself open for a very dangerous situation there.
You would only be able to trust it to the strength of the winch strap, as you would be too far out to use a safety chain. And you would be hanging off the back of the trailer much too far to possibly use transom straps. And if you were, if the boat shifts forward while braking, which it could, your transom straps would now be loose.
I do believe the rule of thumb is to run the bunks within one inch of the transom. And many will run them a 1/2" past. I can't remember if the winch post is welded on our trailers, but if you choose to balance the weight back, take the time to adjust your winch post. allowing you to avoid any movement.
Weight on the tongue is very important for safe towing as well. Balance on these trailers is set at the factory, but as mentioned above, gear will effect it greatly. It will have a more noticeable effect on smaller tow vehicles. You get that weight too far back, and the tail will wag the dog, if you know what I mean.
Good luck,
