One of the problems with the original 18.5 trailer was the keel guides would in advertently hang up the wing bulb keel on launching and trailering.
As for retrieving the boat, the trailer is at an angle and for the most part, you will never get it to come up correctly in the bow roller. As for a longer extension since some felt the original tongue was too short, generally a 6-8 foot extension would aid you but there are many ways to add that permanently or simply chock the trailer tires while keeping the chains attached, release the boat trailer from the tow vehicle, remove the chains if boat trailer is not moving, move the tow vehicle up and add the extension between the trailer and boat.
dave condon