Quick Question on Safestrap Settings topic

So, I downloaded safestrap 3.65 for my MF3 based S4. I opened it up and just wanted to make sure I set things up correctly before I fill one of the custom ROM slots. The default shows the partition size to be 2800 MB, the data partition to be 2500 MB and the cache to be 300 MB (a total of 5.6 gigs). That seems very large relative to the suggestion of the description here:

http://blog.hash-of-codes.com/how-to-safestrap/

(showing 1GB, 2GB, and 3GB, granted it's an older version). I'm assuming this app gives you more control but I'm a bit new so I'm not sure what to use for default settings.

I also only have 2.43 GB free so I'm going to have to remove some things. What kind of preparation do you guys recommend? Wiping phone before creating custom roms? Clearing out all music/picture files, etc?

Any suggestions you can give me for preparing for the custom ROM slot would be greatly appreciated.

Thanks, guys!