Any tips on a good portion for breakfast? I am looking into breakfasting like a king, and decreasing amounts for lunch and dinner as currently I end up eating dinner very late around work and know it’s not healthy.

That’s a good approach towards healthy eating habits. Breakfast should consist of proteins and carbs to make you feel fulfilling for a longer time. You can have grilled chicken/meat sandwich ,salad and coffee or oatmeal with nuts and any fresh fruit available

Any king would rely on a balanced breakfast as the key to a properly functioning day. It should ideally comprise majorly of Two components- Carbs and protein eg- Oats, chickpea flour tortilla, bread and eggs, chickpeas, tofu/cottage cheese respectively. Then to add some nutrients- vitamins and mineral rich foods eg; Fruits, veggies and milk
Last but not the least, healthy fats in moderate quantities; egg yolk, ghee, cheese