The rear of the trailer should be at the rear of the boat to support it properly. There are trailers that have a set or roller bunks that extend beyond the rear of the trailer frame to support the stern of the boat ( I have one), but the one in your pics is not built for that. Without your boat sitting on the new trailer, we can't tell for sure. The new trailer needs keel rollers for sure, bunks should be adjustable, as long as they support the hull all the way to the stern, even better if bunks stick out an inch or two.