Funny that I also thought about clones but you need to be very careful to not let the clone know that he is a clone otherwise he will not work your work and try to work against you. So I. designed a scenario to make sure clones don't know they are clones:
First we assume a clone is an exact copy from flesh to soul, including every little detail of mind you used to design this scenario to cheap the clone, without a technique to erase part of memory.
Now lets say we don't have 100% success rate with cloning, like 3d printing organic material is not always successful. I will go inside a tube, get sedated for a full body scan. The next tube will be the target tube where the clone prints out. Then proceeds with scanning and printing. After a while, the printing is finished but both source and target are sedated. Now remove source, wake him up and tell him he is the original, hide him in observation room. Move the clone tube to the location of the source tube to confuse clone. Now attempt to wake the clone, with another tube and some junk inside. If the clone fails to wake, scrap it and try again some other time. If the clone wakes up, tell clone he is the original and the clone fails to print. Tell him to go back to his job. Will this work?