Say, if my procrastination time is 3 hours per day, I could allocate 10% of that -- 18 minutes. How long does it take to speak a sentence "I will become a syndicated cartoonist"? 10 seconds at maximum -- which means 108 repetitions into 18 minutes!

IAWYC, but if you want to learn to do it correctly, you'd be better off using fewer repetitions and suggesting something aimed at provoking an immediate response, such as "I'm now drawing a cartoon"... and carefully paying attention to your inner imagery and physical responses, which are the real meat of this family of techniques.