establish framework and method
May I suggest that when you are selecting your coach that you make certain that the coach really understands what you are doing that is working and what is not working, wants to determine why, and helps determine where you want to end up and how you will get there. Many people have been disapointed in coaching of various types because the coach knows how to do something as an expert but does not know how to assess and progress the client. Also, try to determine what aspects of what you need to do differently involve knowledge and content (usually fairly easy to deliver) in contrast to skills and methods (usually harder to develop in a client). You might ask the coach what kinds of things he or she does that helps clients develop skills and apply methods and how these vary from one client to another. Also, what is the coach's commitment to and approach to determining what your needs are, what you know (versus what you say you know) and determining the obstacles you need to over come, and finally providing either a range of solutions or some experiences that will help you progress rather than hammering at you what the ultimate criteria is--sometimes coaches have a bit of a one size fits all service. YTou no doubt want more than someone who just tells you over and over what the model is and why you should adapt it. It can be very hard to get to how.
As to fees, although the DavidCo. coaching fees may be "in-line" with similar professionals, and they have the asset of really knowing the GTD model, it is important that you find someone whose fee you can live with relative to the portion of your income you can afford to spend. You may find it more cost effective to carefully search this board for questions that have already been addressed and try on those answers for size. Then if you still need coaching, you have at least narrowed down what needs to be addressed.