Can you connect the SSD to the laptop and then open the disk management window?
Type "Disk Management" inside the Search the web and Windows box - lower left screen, unless you moved the box.
You should be able to see both drives.
Should be able to expand and/or shrink partitions as necessary. (Right click inside the partitions to make the adjustments.)
Just be careful not to do anything at first. Get your "geography" straight and carefully plan changes you wish to make. Back up everything important as always.
Then clone from the HDD to the SSD.
That leaves everything on both the HDD and the SSD.
When you are sure the SSD is working correctly you can delete unnecssary data files there.
Yeah I've shrunk everything down in disk management already. But disk management can only shrink my main partition to 310GB. Despite that this still leaves plenty of unused space on that partition, I'm using Macrium Reflect and it wants to copy the exact disc image, so 310 is still too big.
At least, this is to the best of my understanding.
Oh, and by the way, I will be keeping both drives in the laptop, just want to switch the boot drive.
Thanks for getting back to me!