The main reason for memory on the iPad is for caching the map data for when you are flying away from wifi internet coverage. While it may seem sensible to save money on the slave iPad, it is for the video operator, you may at some time need it to work on the master RC. I would go for the maximum memory you can afford. I have a 32GB iPad Mini 2 as my 'slave' display or is it for the 'master' with the bigger screened iPad Air 2 for the 'slave' video operator?