Data Doubler SSD with stock Macbook Pro HDD, Clone Question.

Currently i am running on the default HDD that came with my Macbook Pro. I also have the Data Doubler and a new SSD. I plan on placing the Macbooks stock HDD in the optical bay with the data doubler from OWC. I will then be installing my Samsung SSD where the stock HDD originally was.

With the two drives installed, can i clone the stock HDD to my SSD and then clear the stock HDD for media storage? Do i have to clone externally?

Hardware:
13-inch, Mid 2012 MacBook Pro
OWC Data Doubler
Samsung 840 Series SSD

I'll be doing the same upgrade soon and given what I've read so far I see no reason to clone externally, one advantage of having both drives in the system is performing that operation once your SSD is installed. Just boot into the HDD and then do the cloning to the SSD.

However, I think I'll do a fresh OS install in the SSD instead of cloning, with both drives in the system I'll keep the HDD as it is for a while, at least until I'm sure I have all I need in the SSD...

Take it up with OWC technicians on live chat. It used to be cloning was a no-no for them. They used to strongly recommend system install and Migration Assistant but perhaps this has changed over time?