external storage for ps4


Console: Headset:
I have installed a 4TB external storage unit to my Ps4 to free up memory for games. As im sure everyone knows at this stage, the 500GB the ps4 comes with, is being eaten up by bigger and more demanding games...(really just cod which is taking up best part of 200GB all by itself).
I think the maximum you can go with external hard drives is 8TB for Ps4..but i was wondering can you technically go over that if you used more than one at different times?
I have also got a 500GB external hard drive with a load of games on so would like to switch between the 2 as and when i want to.