Been doing some research and have come up wanting. Just wondering on the 'best' accessory flash for the X100S. I say 'best', but that means 'best for me', i.e., a relative numpty with flash but a keen learner. I'm looking more for something I can use off camera for single flash fill-in and some general learning and lunacy. I hear the Prince of Single Slave - Zack Arias - uses some Yong Nuos with his Fujis but he is a maestro and I am a.....ummm. Am I best to start with a TTL like the native Fuji EF-20 or EF-42 and graduate to things more manual or can I jump straight in with the much lauded and cheaper off-brands? Appreciate any advice or links to such advice.