Using internet recovery to install Mac OS X on SSHD, then replace internal? I have a USB 3.0 to Sata cable of which I will plug into a 500gb SSHD. I will try to install a completely new Mac OS X on it using the Internet Recovery option. Then transfer all of my files via USB 3.0 from the internal to the SSHD.

Afterwards, I will replace my internal HDD with the SSHD. Will this work? Will it automatically boot into my SSHD seeing as it is the only drive?
Yes. OS X supports external bootable volumes fine, and doesn't differentiate in any meaningful way between an external and internal bootable volume.

I would recommend using Migration Assistant to migrate your files, however, if possible–but you'd need a second Mac for this. A relatively easy workaround is to simply "restore" the external disk using the internal disk as the source. You'll need to first boot onto an external drive of some sort or Internet Recovery (assuming your Mac is new enough) (to my knowledge, the recovery partition won't work), then use Disk Utility from there.


Select the external volume in the sidebar, then select Edit > Restore.
Click the Restore pop-up menu, then choose the internal volume.
Click Restore, then click Done.