The answer is to test, test, test, and eat to your meter. Keep a food diary including portion sizes, record your levels alongside, watch the rises, look for patterns over a period of time.
You need to set your own targets, at a level you are happy with. I don't aim for 4s at all, although they are a nice bonus when they happen. I like 5s and 6s. I hate 7s. Once you reach your personal targets, lower them and see what happens.
It is unwise to compare your results to anyone else. Metabolisms are different, medications are different, degree of pancreas damage is different. Just set your own targets, test, record, analyse, tweak the food accordingly.
You don't need to go overboard with fats, just avoid anything low fat and eat real food. If you find yourself feeling hungry or fatigued, add a bit more fat for energy and fullness..
This is all such good advice. You have given me such hope .... I CAN achieve the same level of control as you and I will ...... though it will be so nice having all you guys to help when it gets hard ...... and it does sometimes! Very. Does it still get hard for you ... how do you cope?