Just have a few comments ... as this thread is getting confusing ...
First off, you don't put the MCT onto a flash drive -- as that is a utility that is used to DOWNLOAD the files needed to either update the PC in-place or create install media. What you do is USE the MCT to create the install media.
Second, the media itself, presuming it is a USB stick, only needs to be 8GB as it only contains Windows installation files.
Third, you say you have a new SSD in your PC, to install Windows to it, all you need to do is boot from the USB stick and go through the installation process. When you get the screen prompting for a product key, choose the option to skip that -- as once the OS is installed and the PC is online, it will contact the MS servers and reactivate Win10 automatically.
Fourth, if you are only going to have one physical drive in your PC, then it certainly needs to be large enough to handle the partitions currently on the hard drive up to the amount of space used. If your 1TB drive has less than 250GB of space used, there is a way to "migrate" your current partitions and OS to that size SSD, and that's what I would do -- as 1TB SSDs are still very expensive.
So, let us know what it is you really want to do.