Is this a tricky factor when you are looking for certain specs? E.g. wanting a female golden cocker?! Do you commit to a breeder before you choose a pup? Or visit litters hoping to pick? Or if a breeder likes you - can you ask them to reserve a chilled out golden? Sorry! That's a lot of questions!
In my experience, it is very difficult to find a breeder and a pup. They usually have one 2 litters / year and their waiting list is long. At least in the USA. I doubt that you will have the opportunity to go to 3-4 breeders when you plan to bring the pup home, and choose just the right one.
Yes, you can tell the breeder what you want, and to keep the pup for you, but you have to place a deposit and this is 2-3 days after they were born.
In our case, my breeder will give us the pup she thinks is right for us. I just told her who we are, and what we are looking for. Given that she sees the pups for 10-12 weeks she knows better their temperament. Although the look is important, don't make it your firs criteria of selection. If I were you, I would find 2-3 breeders, tell them precisely how is your family and how do you want the dog to be.
Good luck.
I looked for a pup for a long time.