ZFS ZIL L2ARC 16GB RAM 10GbE

Hi,

I am new to FreeNAS, I have some design questions.
I want to use it for shared NFS Storage for two Proxmox VE Systems.

My Hardware is:
Intel Xeon X3430 CPU, 16GB ECC RAM (MAX)
3x 32GB USB Stick for FreeNAS System
2x 4TB 7200 NAS HDD Mirror
1x 2 Port Infiniband 10GbE NIC
2x 160gb Intel 3510 SSD (not used yet)

Do you think I can get better performance with the SSD ZIL and L2ARC?
I read in the forum it isn't good to use ZIL/ARC with only 16GB RAM.