Flight schools use a duchess or seminloe for training because they are cheap, not because they provide good training. If you have the money to buy an airplane, you can afford better training.
We all know that an aircraft in flight is a lousy classroom. Learn the engine out drills in a simulator, so you don't waste expensive time doing so in the airplane. If you are instrument rated, definitely do engine out approaches in the sim.
Then train in a challenging airplane such as the Cessna 310 or a twin Comanche.
Joe