I had it set up as 2 x 1.5TB
I added a 450GB partition to one half then another for an OS X partition. 1.5TB Media 1TB Backup 450GB Recoverdisk 50GB OS X installs OSX.
Im unsure the way i did it because i did OSX with a parallel of windows on it, Virtual 250GB Drive and all OSX installs on it. so it was ~68GB and a smaller OSX partition with other Version
I went into El Capitan Disk utility and resized to get rid of the smaller partitions id created. Moved the lines to resize, Drives dropped and then i had to find a way to recover all the data.
Found Testdisk early in the process, it scanned and i wasn't quite sure i was following the instructions properly, after a scan, or a couple of scans, the missing drive appeared in the thing as D and Green and flashing.....im not sure, it seemed like i was pushing my machine and it kinda glitches a bit and the delay got me and it skipped ahead and missed it.
Ive run the deep scan, see attached
Cheers,

Dave