Can I install a second SSD in place of the superdrive?
I just installed a 960 GB SSD to replace the HDD in this MacBook Pro.
Can I install a second SSD of the same capacity using the Second Hard drive kit sold by iFixit in the Superdrive Bay?
Is the procedure the same as if I were replacing the superdrive with an HDD or Hybrid?
Yes you can this guide will run you though how to install the second SSD, be careful when ordering the caddy as there are two sizes, one for Macbook Pros (Slim) and one for iMacs (normal).
I hope this helps, if you need any more please just ask.