Now, I have not heard you sing, but I have heard your wife sing on several occasions. She has a great voice quality and she interacts very well with the audiences. The reason I offered the information about the voice lessons at the colleges, is because at the very first part of your post you said no one would want to hear you sing for four hours. Maybe the would after the lessons - I don't know. When I was in Nashville, I came across a lady that offered articulation and diction courses for up and coming singers. During her career, she worked with a huge number of the nation's top singers and had rave reviews from them all, including Elvis.
All the best,
Gary