You can need swap file with windows, it is about 16-32GB usually. +Windows. So at least - 16GB, better - 32GB, the best - 64GB. Or SSD, they costs not so much if they are 64GB or less. Or Linux-based mining OS. It is really simple. I don`t remember now how to correct bat file 
Is SSD a good option? I don't think so cos USB drives consume less energy than a SSD, it's better if OP goes for 32GB USB drives to load windows, this will safe more energy than SSD and HDD, if OP wants Linux then 8gb is more than enough for any Linux OS