Warning, spoilers ahead:
The main challenge here seems to be the formation of the "planar" face indicated by the small blue dots in the image above.
If this face is made planar, the model will not match the given dimensions.
The only solution I found was to NOT make the face planar, and instead allow it to be slightly curved/twisted.
I thought I solved this in 4 Features. Now I am unsure if my solution is correct. The dimensions match as well.

If I recall correctly, I was unable to form the little triangle at the base of the model on its right side with the correct dimensions if those 5-sided faces (also on the right side) were made planar.
It made no sense that such a "simple model" would require exotic curved faces to be used.
See if that little triangle has a width of 1. and a height of .5 I also made an assumption that the small trianglular face in question is perpendicular to the top/bottom of the model.