How big is too big to start out?
I would think that 18 inches to 2 feet is a reasonable max before you need special trailors and gear or specialized ramps. In many areas there are two and three ton lifts which are an easier, faster and gentler way to launch. It is also easier on the trailer since it never goes in the water with a hoist. Around here, hoists can often accomodate 5 to 6 feet of draft.