To aid you with finding the parameters, argon2_cffi offers a CLI interface that can be accessed using python -m argon2. It will benchmark Argon2’s password verification in the current environment. You can use command line arguments to set hashing parameters:

$ python -m argon2 -t 1 -m 512 -p 2
Running Argon2i 100 times with:
hash_len: 16
memory_cost: 512
parallelism: 2
time_cost: 1


0.418ms per password verification

This should make it much easier to determine the right parameters for your use case and your environment.