So, perhaps post a price check thread with all the ponies who have flaws and ask for advice?
that's what I would advise too
Also definitely mention all flaws - even tiny ones or factory flaws- when you're selling ponies, especially on ebay and do as many pics as possible. Describe it almost as if the potential buyer knows nothing and needs everything explaining without using collectors terms too (unless you describe what that means ) . Avoid using the word "cancer" as some non collectors (and even some collectors) have had issues with this in the past- use something like brown splodges, age marks, brown dots, darker patches etc so that you avoid potential issues.
It seems like a lot to take in and do to start with but you'll soon get used to it and find it easier when you've sold a few times