Aldogo,
The one question, do you already own a sailboat looking at the referenced MacGregor. The reason I ask, Benny pointed out what many would overlook. The 18-19 length boats are more tender but with proper training from a friend, instructior, etc., that can be overcome. Also be concerned about a deep fixed keel boat.
Once, I had sold a trailer to an elderly gentleman with a Minuete 18 daysailor with a fixed keel. The buyer refused to purchase an extension as he was giving it to a relative in Annapolis. The owner was 85. The keel itself was about 6 feet long from the hull; thus the water line was deeper with the hull. Since they were filming What About Bob at the private club, I was told to hurry to off load that boat, thus no extension of any kind. I drove back fast enough to try and jerk it off the trailer. My car came to a stop with the water about 5 inches above the drivers door. I left the engine on so no water would come up thru the exhaust into the engine and put the car in park with emergency brake on. It was an Impala with all braking on the rear. I dove out of the window into the water and swam back and started trying to jiggle that darn boat off. I then Heard "CAR 54 YOU ARE SINKING." When I turned around, my car was floating backwards into the lake with engine running and at that point the boat came off the trailer as the trailer was in deeper water. I watched the front end dive like a submarine with engine running. The motor gasped it's last breath before dying out and someone yelled out "Dive Dive Dive. Needless to say, I pulled the car out and opened the door to let water out and saw a 20 lb stripper fish swim out. A few months later with everything falling apart inside the car, my daughter age 8 at the time looked at me and said, Dad, we need a new car. I guess she was embarraresed and from then on, larger and four wheel vehichles was a must not to mention equipment to carry if I ever attempted another launch like that above. The only thing I now wish, the film crew actually filmed that launch and wanted to put it in the movie but I said no due to being embarrassed. I regret that decision and I lived up to my nickname, Crazy Dave