I know the memory is very limited on the Arduino so I'm trying to figure out the best way to do the actual project, which is to play back the 4 signals over 1200 seconds, one point per signal each second.
Personally, I would just send the data off the Arduino (use a Leonardo 32U4) too a PC over the USB. Collect the data in Excel.
Excel can then parse, analyze, graph, ...
Here is how to parse using formulas... No VBA required!
http://www.hackster.io/rayburne/arduino-to-excel-using-v-usb
Ray