Hunting Dog Training

I own a Springer from working stock and recently, I’ve been doing basic gun dog training with her, she’s picking it up quickly and doing really well.
I’ve just returned from training classes. The classes are for obedience and agility but one of the trainers has fully trained gun dogs that he competes, trains, works and demonstrates with, so he takes me aside to do gun dog work while the other dogs do the agility. Today I was asking about competing in field trials with her if she completes all her training and he said the only problem would be her tail, so now I’m looking more towards the YKC junior handler field trials because of her tail.
My question is, does anyone have any experience working an undocked dog?