Looking at getting a ryzen 1700x. Can you mine multiple instances of the java miner for the multiple threads? Is it only the python miner that allows this. What would the hash rate be that I am looking at?

Java miner also does multithreading (more then one hasher) and also supports affinity, and best-effort stable memory use for max speeds.
Read a bit about it here:
https://forum.arionum.com/viewtopic.php?f=11&t=28Ryzen 1700x with a good (max memory channels, high bandwidth) memory layout can get 25-30h/s iirc. Some tweaking may be required, it would be best to join the discord #mining channel so that other Ryzen owners could give you a hand.