I have been on a PMR journey for almost 1 1/2 years. I like (and consult) this Mayo Clinic site. Another site that has been helpful is healthunlocked.com/PMRGCAuk — a British site with a lot of members who have or had PMR and GCA. The main posters on that site are NOT doctors, so their suggestions are not medical advice, but they are experienced about PMR. They advocate a slow taper of prednisone. A rule of thumb often mentioned is not to taper more than 10% of your current dose. So, for 15 mg, the maximum taper would be 1.5 mg, and you might spend 3-4 weeks there before lowering again. I am not trying to give medical advice, but this approach has worked well for me so far. Everyone’s PMR journey is a little different. I wish you the best on yours.