No one could have possibly foreseen how long it was going to take to complete the Guidelines and Standards for Tactile Graphics publication!! Even the committee members themselves have predicted several times that they were almost finished. It is my understanding that they have devoted the past year to addressing the many concerns expressed by the reviewers. They have now submitted a greatly revised edition to BANA for approval. I can certainly understand your frustration over which guidelines to follow in your transcriptions. Others have found themselves in a similar dilema. The best answer that I can give you to that when you work for several different agencies (or proofreaders), discuss and establish between the two of you what the expectations are for each particular contract before you get started.
NBA has already given workshops based on the DRAFT document, because the guidelines are generally based on "best practises" that have already been established by many individuals and agencies. Yes, there are a few instances where the guidelines will differ from the Guidelines for Math Diagrams, and those are the exceptions which will have to be discussed between the transcriber and proofreader. We are offering another tactile strand at the NBA conference in Raleigh, NC, in October. Even that material has been delayed in the writing stage in hopes of getting the very latest information from the committee that is working on the guidelines. Rest assured that there will be announcements from BANA and NBA when the guidelines are official adopted!