RAID question

Let's say you have machine with 64GB of RAM and 2xSSD drives. What is the most best way of running ES on such machine? Would you run one instance on RAID 0, or two instances with half as RAM, but each with separate SSD drive. One of instances would have to share disk with OS.

Memory-wise is 31/32GB reserved for ES recommended for 64GB machines?

I'd run a single node myself.

For heap, see