Is there a way to get higher redundancy then that:
"The uploading process is as follows. First, the file is striped into chunks of 40MB. Reed-Solomon erasure coding is then applied on each chunk, expanding them into 30 pieces of 4MB. Erasure coding is like an M-of-N multisig protocol, but for data: out of N total pieces, only M are needed to recover the full 40MB chunk. This ensures a high level of redundancy, much greater than traditional replication."
AFAIK this is hardcoded today, and making it configurable is not on the roadmap anytime soon. Why would you need more? They say it's like 99.99999% or more (it's in their papers somewhere).
Also did you check these links? https://forum.sia.tech/topic/1514/redundancy-fault-tolerance