I assume you did that banding job? It's not bad, but you're not quite good enough to do white yet.
You need a lot more practice on making them straight and flat, and subconciosly you'll do this every time you band. Look up videos on you tube to get some pointers. Just go out and randomly band your horses. Mine put up with it for a long long time, as I would experiment with widths of banding sections, lengths of manes, etc. to see what made them look best.
I personally never band a wet mane anymore. I use to - but it makes the hair very weird when it's done. It's easier for me to do a dry, clean mane. I don't use any product except mane mousse after it's completely banded, and I use a mesh mane tamer.