Here's an updated drawing, using 5.0 as the total width, which can be easily adjusted if needed. This drawing is to scale, which shows you how the proportions will appear in cross section.

scale dimension image.jpg

Let me know if this is correct and acceptable, and if you require any changes. Please consider how any change you request will affect other dimensions. As an example, if you require 5.5 mm across the bottom, which other dimensions will be changed and by how much?