IMHO there’s no good reason to try to maintain10% unless someone is paying you. Take a pic at 10% for your dating profile and live your life at 13-15%, just knowing it’s possible to get back. That’s why there cutting and bulking. The hardcore fasting routines are for getting the very large going in the right direction. Models, bodybuilders etc don’t maintain that level of leanness long term. Just my opinion. Be safe.
Why are you trying to maintain such a low percentage? Are you going to compete or model with it? At this level of leanness, with regular intense training, 72 hour fasts are out, and 48s probably are as well. It’s also going to be pretty important to consider what gear you’re on, if you’re that serious. You’re probably going to be doing some sort of OMAD no matter the details.
I haven’t done that, but theoretically you will need to manage body heat ( cold showers/baths ) strict diet… lots of sleep , check Tim Ferris’s ( last 5-10 pounds ) protocol ! That combined with a weekly fast ( 48-72)should get you there .