I have discovered an easy way to reduce the arc file size, unfortunately it requires losing a feature of the game. In my case I chose to get rid of Create-A-Belt because I never use it and dont plan on ever using it.
Just getting rid of CAB from my arc reduced the size by 4kb which means 256 more attires or 128 new wrestlers.
Tutorial
1) Make a backup of your plist.arc and .def files.
2) Open your plist.arc with a Hex Editor (I use Hex Workshop)
3) Do a search/find for the TextSting