[tor-relays] Documentation on hardening Debian and Tor Bridge?

Hi,

What documentation, if any exists on hardening my Debian install as well as my Tor Bridge? It's using OBFS4 and using IPTABLES NAT Forwarding for access through port 443 to obfuscate the protocol and of course avoid people from getting suspicious based on the port number? Is there a way I can make Tor use even stronger keys and such? I want things to be as hard to hack as possible.

Cordially, Nathaniel Suchy