If someone is looking for a course or hands on training in sleep they should first know what their goals are. Do you want to add sleep to your general dentist practice or are you wanting to do a sleep and TMJ only practice.
Reading my book or attending an low cost intro course from the many people an companies teaching them is a great beginning. See if this is really what you want to do before investing a lot of time and money.
You also need to look at the rate of return on your course investing. If you spend more than $10,000 to take a course than you will need to do a lot of dentistry to pay back the cost of the course and the equipment. Think economically before jumping in.
If you wish a sleep only practice you may need further help with that.