Step notch size?

[thrtsxchambers]

I am wondering how tall the metal should be for a step notch? I have one that is 4inch tall on the top and the sides are 5-5.5 inches. I would like to chop the top down some and I then may be able to have a full flat floor. The floor is raised 4inch already and think if I can chop it 1-1.5 inches I can have a full floor. I don't want to raise the floor anymore if I don't have to, just wondering what sizes you guys use. Pics would be good if you can also.
Thanks in advance.