Unless you’re absolutely bonkers with hunger maybe work to a 20:4? Where you “break fast” with something you know isn’t supposed to be a meal, and knowing your “big feed” is still to come. If you’re targeting a 2,000 calorie day maybe 500-1500 one way or the other makes sense instead.
I strive to get as much fat content into my meals as possible. I get “comfortably stuffed”. I have not been hungry in months. I do a full fast once a week for 36 to 48 hours, and 18/6 or 16/8 other days. This might work for you, we are all different, but it works for me. My goal is not weight loss but health. I have lost 17% of my total weight in the last seven months but that is just a bonus. Rollipullit thinks you should stick with 18/6, I think what you eat is just as important as the length of the window. Losing insulin resistance was my key. I have no trouble staying in the 170’s and I average 2500-3500 calories daily.
I just started IF with the intention of 16:8 but usually end up doing 18:6. My first meal is 300-400 calories and that’s enough to get me to my last meal which is much larger calorie wise. I aim for 1,000-1,200 per day(total). I’d eat that last meal regardless if I was hungry or not just to help get your through the fast.
I’m pretty early on with IF and calorie counting but I’m also doing 18:6. It might be worth trying to eat less for your first meal so you can get in more calories later. I don’t have much data yet but for example - my first meal has around 400 cal and my 2nd meal has around 650 cal. Allows for a snack or two in-between. Of course, this all depends on your daily caloric goal.
Consistent 1000 calorie days will probably bring you into crash diet territory, and that’s not something you want to do. I’d go back to 16:8 and do your best getting adequate calories and nutrients in.