I think you need to do both to get better results and you will have a good understanding of how to work with them. With PSA`S you will be coaching and learning at the same time and with new affiliates you will allow them to get into the depth of SFI. They can learn and copy your work with their own PSA`S and in turn sponsor new affiliates,they will look up to you as their leader.
You will find out what best works for you after you sponsor PSA or new affiliates!