Hi Teresa, I've always gotten great plants from Ken. He has pictures posted on the LA under his ID showing the size and he gives the "date of birth" on the auction listing.
I have bought many seedling on the LA and 98% were the size listed. Just remember that a 3-6 month seedling can be 16" tall and it will take atleast a full year before bloom in most areas. Also, if these seedling don't get some TLC they may not bloom for 2 years. Now, if you happen to have one of Fred's 6 month old seedlings they'lll be BLOOMING!!!! But, we all know just how special Fred is and he has that Magic touch to grow seedlings to bloom in 6 months. An amazing thing.
I think that the grower really should show pictures of the seedlings if at all possible or atleast a photo of something similar. I bought some seedlings earlier this year with a statement of them being nearly 18 months old and they were. They were huge plants and I was very happy. I showed pictures above of them.
If you ever have any doubts about a Auction seller, you could ask on here. You should get a good answer unless the seller is really new.
Blessings, Mona