If you want a clean install, you have to first get on the free upgrade band wagon and get win 10 on. Make sure after its installed it has been activated.
You can then use the upgrade tool from Microsoft to create a usb or DVD boot disk.
Get it on your new ssd (without installing win7 first) skip the parts that ask for your windows key.
Once it's done and has connected to the Internet, it will identify your hardware and activate windows.
This is typically10 the normal way to do it.
There are a few good guides online that will help if you run into difficulties.
I did this on my sons pc and it worked a treat as he was having bother with a faulty Nvidia Gfx card and I wanted to rule out the os.
The only thing is you will get stuck with the size of your ssd as the upgrade leaves a large restore folder of 35 to 45gb depending on what's to back up so yes an imaging tool is the way to go.
Personally I would start from scratch on a new drive with win7 then do the upgrade, then I would format it and start again with the the win10 boot disk and set the old ssd as a secondary drive and drag over whatever files then reinstall my other bits of software, I found that just upgrading to 10 from a win7 install leaves a lot of crap behind if you don't know where to look for it, probably just OCD !
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