I can't yet speak from experience, but from reading, I think the following are markers of a good carbnite:1. Spike insulin with quick absorbing, rather than slow release, carbs.2. Feeling of psychological satisfaction at being able to have foods that are forbidden on low-carb days.3. Feeling ready to start the next 7 low carb days.4. Not too high in fat.5. EnjoyableI can't really comment on the macro ratio breakdown - but I will be consuming at least 600g of carbs on my carbnite. 400g seems quite low - but everyone's different.