"Enough" food versus the hunger scale

I’ve been doing intermittent fasting and following the hunger scale -4 to +4 for over a year. I do 23 hour fasts a couple days a week and 18:6 most other days. When I do eat lunch it is often small as I am on the go and not yet overly hungry. Dinner is sometimes confusing for me still. Sometimes I am not that hungry but I know I should eat as I don’t want to fast to excess. It is hard to truly start eating at a -2 or -4 bc sometimes that comes midday and passes, then I am not hungry at dinner. Sometimes I an-hour get- very hungry and eat a LOT (on plan and I usually don’t sweat that, since it is basically my day’s calories). Other days I am not yet that hungry but once I start eating I suddenly drop from-1 to -4 for a little bit! In terms of dinner planning- should I just plan ahead for a large quantity (like most of my day’s worth) of food and then not eat it if I am full? Or plan for a smaller amount and then just eat more of that on plan food if not to +4? I want to be sure I am fueling my body enough that I am truly fasting, not calorie restricting, if that makes sense.. and am struggling to decide ahead of time on the “right ” amount of food. Thanks.