I second HDD Raw Copy.
also, i have a HD dock that does standalone bit for bit cloning that has worked out pretty good and it's fast too. i can clone a 500gb sata SSD drive to another SSD, bit for bit, in under 10 mins without using a computer.
I have the older version of this...
https://www.startech.com/en-us/hdd/satdock2reu3
I think this is the way to go.
I have a somewhat similar duplicator, it's supposed to copy bit for bit without any software shenanigans.
It's worked for cloning bags, silver strike, pga tour team challenge, and several megatouch drives with no issues.
Op, just to be on the safe side, go with the same size or a slightly larger drive.
Partitions may be spaced oddly on your original drive, even though all the space isn't used up.