Intermittent fasting AM vs PM


I am watching and reading Brooke’s teaching on intermittent fasting. I love and have been doing it for years (I learned about it from other resources before discovering SCS). Is there a reason to skip breakfast and eat from 12-8pm rather than skipping dinner and eating from, say, 5-3?? Also, I see that Brooke allows coffee and cream during her fasting periods. I drink bulletproof coffee (and tea!). Can I drink coffee with butter when fasting. Would adding collagen powder for protein be ok or would that start to be more like eating?