If you got the Data Table to work I would go with that.
That is a good solution, good job I learned something too... I did not think of the histogram then break down by timestamp 
You will have that extra timestamp first column not sure what to do about that... you could shrink it to the left as far as possible.
With respect to saved Search :
- The names of the columns are not user friendly. Is there a way to customize these fields?
Yes you can do that in the in the Index Pattern and Edit those Fields and add a Custom Label but then that friendly name will show is a number of places Discover, Maps etc.
- I can't adjust the width of the columns like I usually do in tables.
Correct, that is currently a limitation that is in the backlog, I believe.