That's pretty much exactly what i was doing, only in long drawn out stages, as i needed to be able to work on the laptop in between stages.
You were right about the double installs (or at least the problem hasn't persisted) nowhere could i find it said that you couldn't have a cloned version of windows.
What i did today (after faffing about with it last night too) was to clone it all again using Clonezilla, which is a much better tool than EaseUS. The first time i did it, it tried to just clone the partition with Windows on it (my C: drive), but that wouldn't work; the cloned partition wouldn't boot. I reckon it was because it needed some files from a different (OEM) partition on the HDD. What i needed to do was clone the entire drive rather than just the partition with Windows on it.
So i had to delete more stuff, and tell the Clonezilla program to ignore the fact that the clonee drive was bigger than the cloner drive, and this morning I had two identical drives.
Too identical, it turned out, as they had the same drive ID, and one of them wouldn't come online. Doh!
However, with some faffing they eventually sorted themselves out, and had different ID's.
Anyway, i am now writing this on my laptop with my old HDD sat beside me disconnected.
Success!
/thread.