Quality of bi luo chun?

[Mintaka]

What are some of the ways to detect the various levels of quality of bi luo chun? I've looked at various ones--shape of leaves (degree of curliness), color, aroma, and of course the taste of the brewed liquor. But how would (or do) you judge the quality of bi luo chun? I ask this specifically because it's one of my favorite greens and I know I'll buy more in the future. I want some ideas as to which are best in your opinions (i.e. buying sources online) or ways to judge the quality in person (local shops, etc.).

Thanks.

[ChinesePottery]

Personal preference is a big factor and if you like your BLC fresh and a bit sweeter like me, I'd go for smaller leaves. Before I buy I do brew a bit and let the leaves expand, I don't just judge by the curly dry leaves. Take a good nose full of the aroma after the wash and do make as many steeps as you usually enjoy/expect and see how the tea performs and changes throughout. I like a good amount of 'frost', the downy hair that comes only from the middle bud, as it produces a very 'hairy' tea. Machine made BLC can often look superior in appearance, as often does autumn harvested BLC, but they are not the first choice of course. Very uniform rolled leaves can be a warning sign for me to stay away.
To the semi official and popular grades like supreme or gradeX I don't pay much attention and let others worry about those.