I’d say no later than 7. In my opinion you’re doing exactly the right thing because for me OMAD dry is the best weight loss protocol hands down. It teaches you great fasting habits and you don’t have to deal with the scale going back up after a prolonged dryfast because of the water retention, it’s just a good solid drop each day.
I’ve found that if you throw about 40 mins of Jump rope in you can burn about 1.5 - 2lbs a day and it’s manageable because you’re either drinking fluid during your workout or right after. Although I was eating super low carb I when I did it i.e just fatty meat of about 1000-1200 calories a day
For me it’s break the fast at 4/5pm with tea. Then eat whatever I need to before 7pm. Then begin the next fast.
So basically 20/21 hours dry, 3 hour window to refeed and rehydrate. Then begin the next fast. I feel pretty damn good doing this.