Whichever one you can keep doing is the best one for you. No sense trying 23:1 only to quit 3 days later and feel like a failure. Try 16:8 and see how you feel. If you don’t get into a good enough fast, try 18:6 and see how that feels. I’m at about 19:5 and I’m trying to get and stay at 20:4. I’m also considering trying ADF (alternate day fasting) and omad.