With the exception of how you set up the offset of the bores ("D2@Boss-Extrude4" = "D" - 10 - I used offset in the extrude feature), everything looks OK.
The one thing I did differently was to make some of the dimensions equal to each other. For example: "D1@Sketch10" = "D1@Sketch8" instead of having both equal to "E". The same thing can be done for D and C. It may help your processing time.
I completed the first segment of the core exam this past Saturday and I had no problem with time. You'll probably be fine.