GNaNA
You might wanna change the hight of the wall a bit, becouse 8 meters in westerosi standards is a children's playground. Winterfell one of the few keeps that we know a lot of details about, has an outer wall that's 25 Meters high and a inner wall that's 30 Meters high. I think i read that King's Landing has a wall that's 20 Meter high, i could be wrong though. In the future when you think of a castle take the real life standard and multiply it by 10 and you should have the parameters of a average westeros castle. Just to give you an example of that, Harrenhal castle gate was 30 meters long, (not high, not wide but actually long as in you would need to walk 30 meters to get from one entrance to the other). Now granted Harrenhal was the greatest Keeps EVER but you get the pictures of what they are capable of