well, very simple: DON'T use SET and fully understand what you are trying to achieve!
ReL1K includes already good options to create the appropriate payloads and if you are
not satisfied, add your own adjustments in src/payloadgen/payloadgen.py & src/msf_attacks/create_payload.py & src/exe/legit.binary
don't simply execute tools, understand the foundation behind it. I highly recommend to
understand the attack vectors used in his tool and do extensive manual testing.