I found this post interesting and helpful... I just took a FMQ class Saturday on my DM and had my first experience with feathers. Our first attempt was on a pre-drawn panel and that was difficult enough. I found when I drew my own spine and then went down one side I did okay, but going up the other side was wonky... so then I tried it the other direction. Clearly, your brain is more comfortable in one direction than another but the class certainly gave me the confidence and motivation to work on feathers.
Anael, your feathers are wonderful and I hope to get the hang of it as you make it look easy.