So yes you’re right it is advised that you don’t go from a water fast to a dry fast, because this is extremely stressful for the body. Water fast to a dry fast is the better way of combining fasts.
It isn’t clear why you think you have a specific issue that hasn’t been addressed. I’m not sure what that is, do you mean that you want to lose another 8kg in 8 days for a “critical weigh in”? What do you mean by critical?
The way I see it, as you’ve successfully done a 7 day water fast and you want to carry on with some kind of fast, you should just continue with water fasting. Then once you’ve refed and are fully recovered, you should think about trying dry fasting.
8kg 8 days is tough
What are you weighing in for? if it’s fighting sports your brain takes long time to rehydrate and that might make it take injuries if dehydrated
You might look at HIIT training / tabata while fasting to get metabolism up and crazy - you can change your fat burning level to nearly double - from 1.2 to 1.9. Basically, your body can only get food from fat if you not eating, so if you do intense stuff like that it theoritcally multipliers up.
basically find a tabata timer and for 20 seconds do as many burpees as your can, and rest 10 seconds, 8 times. It should be incredibly hard, and thats the point. Every time try to get the most you can to make your metabolism go crazy.