how to know how much to increase Prednisone dosage during flare

I have PMR and tapered down from 20mg/day to 2 mg/day of Prednisone over 15 months. Then, yesterday I woke up stiff and in pain all over. Obviously flare and I am waiting on my doctor to advise me but he has been busy. I decided to take 5 prednisone today but it isn’t enough. How do I experiment to find the correct dosage now? My right hand is swollen and useless so I cannot drive and my hips and knees are painful so I cannot go out of my apartment. I have always had to split my Prednisone dosage taking ½ at night ½ in day, which makes “experimenting” with dosages confusing.