James,
As TheTick recommended, get rid of anything you don't need: User Notes, your notes, etc. If anything is common to all configs then it is not needed either.
I see that you are using multiple tabs in the spreadsheet. This is good and an often overlooked capability of the Design Table. Perhaps you can make more use of these tabs by moving any intermediate items, such as calculations, especially ones showing intermediate results, to these other tabs. All you want on your main tab is the minimum list of items that change.
If you are using fasteners in holes and need to handle the different fasteners and different quantities there are a couple of things that may help:
1) Change Configurations of the fastener rather than supress one size and insert another. For all the fasteners of the same type, but different size this will save many columns and maintenance of the DT will be much easier.
2) Put the first fastener of a given type in the first hole of a series created with the hole wizard. I recently discovered this and am so thrilled. When creating a series of holes that would be in a pattern I used to create the first one by itself then create an appropriate feature pattern, such as four holes on a bolt circle. I have since learned that all I have to do is put four positions (sketch points) of the hole in that single hole feature. In the assembly I then insert a fastener in one of the holes, then use Feature Driven Component Pattern and select the hole wizard feature as the Driving Feature. Now if the number or spacing of the holes changes the fasteners change to suit. The only trick here is to place the fastener on the first hole of that hole wizard. This is easy to change the mates to the first hole if you don't get it on the first shot.
- - -Updraft