Hi Caterpillar,
agreeing with your last comment, just getting on with it really is the only way to go. Guide numbers of 12k is near enough, mine was about 19k but it "worked" and, as someone else said below, you will find that you will end up following your own lead.. if that makes sense. Your PhD will be different and will require a different approach to most others you'll read.
Getting on with it teaches you as much about what you leave out as what you leave in.
You sound like you have a great attitude and are enjoying it.. what more can you ask for? Chuff