To estimate the file size for your speedrun, you could start by recording an hour of gameplay at your intended settings of 360p with a low bitrate. Then, check the file size of this hour-long video and multiply it by 288, which is the total number of hours in 12 days. This calculation should give you a rough idea of the total storage needed.

You might enjoy running The Witcher 3 or Fallout: New Vegas as they both offer complex worlds with lots of speedrun potential.

Perhaps there are interested players here and we can create a Discord? I saw that there are players for Casino Kid too, and there was no Discord, but that was a few months ago. Perhaps something has changed?