I have used Timbos method years ago to get a ball park. I just went down stairs and got a yard stick and checked using this method. I measured about 27” on the yard stick. My wood arrows I shoot 3d with are cut 28-1/2” from throat of nock to back of point. At full draw I have about 1/2” of arrow sticking out past the back of my bow. Other factors can affect your actual arrow length, as in handle/ grip size and shape, so YMMV. I would just go slow as you approach 27” or so, start checking your draw length slowly without overdrawing, or shaving off too much weight. You can always take more wood off, but you can’t put it back on.