What's the Most Efficient Way to Program This?

[puggsoy]

-Binary Data instead of pure text:
-->PRO: Data becomes more compact and should be faster to read in. This means, reading in stats can be done right before drop and avoid arrays altogether.
-->CON If you don't have experience looking at raw binary data or hex values, creating files would be confusing. -If you do it by hand. (Make a small program to read/write files)

Just wanna say I agree with this. Obviously, if you're not experienced with binary data and/or Game Maker isn't fit for handling it, text may be easier. It's probably easier to write too (unless you make a custom tool to create these files).
However personally, once I understood how to work with it, I highly prefer binary files over text or XML files. It's smaller, easier to parse (from my point of view anyway), and probably quicker too.