Perfectly acceptable. In fact, on most street cars, setting timing by ear is just fine. The only think I might recommend is to make sure the total does not go to high. You can do that with an FBO limiter plate, but I don't think that's necessary on a stock engine. In fact, you're likely not going to hurt it even if you get close to or at 40 degrees total. It just doesn't have enough compression to get in trouble.
