http://dnbible7sqskwppgaqohboxz7u5kzffjzdx3lxzpjtt3s6tzeiytb5ad.onion/bible/operating-systems/whonix/performance_tips/index.html
They do not need to have much capacity either for this use-case, 50 or 75 Gigabyte would easily be sufficient. If that is not an option consider using a USB 3.0 stick on a 3.0 port over a 2.0 one which gets you better results. English English Spanish French German Performance tips Using more CPUs for the Workstation Reducing the RAM for the Gateway Using an SSD