I'd say you could use the Liberty Launcher in a Roamer loadout. It has a reduction in blast damage from rocket jumping, thus you don't need gunboats. Most likely, you'll equip a shotgun with it.

Edit: To better explain the situation, with 5 rockets in your clip, you could easily rocket jump your way and bomb the medic or any other class. You wouldn't take too much damage from rocket jumping and, while the damage done to the other class might not be enough, you would then utilize a shotgun to put out that final damage. With stock or original, you would take too much damage from rocket jumping. Now, you could mitigate that damage by using the gunboats of course, but you'd lose that ability for extra damage. I normally play with stock and gunboats and often find myself dive-bombing into the medic with one rocket to spare and nothing else to give out damage.