I decided to take this Kata in a different direction by using it as an excuse/reason to learn more about how the software I create on a daily basis is affected by this (if anybody desperately wants to see the calculations from me doing the other part - the original kata I will upload them but I expect there are a few copies of the same information around the Internet).
The force.com platform I use has a developer environment limit of 20MB of storage. Each row you save on an object/database takes up 2K no matter what it is. So that works out to me as a maximum of 12040 records.
This is then limited by us adding our code base to the org to actually have objects we require to use and so on. Still I found it interesting to learn some more about documents etc.