preordering advice

Artists do both setting a limited amount or taking unlimited amounts until the ordering period is over. I think it would depend on how many orders the artist can handle.

 

I think this is something that you can't decide until you have the peroduct ready for sale. I mean, for myself, deciding on what the interest for the doll has been is vital to deciding how and when to open an order period. It's also a deciding factor in prizing and the length of preorder time.
If you do it for the very frst time and have very little or no fanbase, no oppurtunity to test peoples real life reactions to your doll and no previos products out there, you can't expect to sell many dolls and so you may have to be ok with a few failed order periods before you reach your minimum requiered number of dolls to reach break even.
If you are casting your own you can still produce the few that you did get orders for (just make sure that you can cover the cost of making the molds), but if you use a casting company, you can't just pay for the rest to reach minimum number of orders yourself, that's a sure way to loose money and end up with unsold stock.
If you, on the other hand allready have a following, perhaps allreday a fan base that buys other art related things you do so that you are allready on the map, so to speak, or if you made a doll so spectacular that people show continued interes during the sculpting process, then perhaps you can take more of a risk. But be aware that most doll artists don't sell many dolls on their first try.
There is also the bitter truth that typically, nobody is very good the first time they do something. Most peoples first doll projects are no exception. The quality of the work is one aspect. The other is working hours spent versus pey per hour for the artist. When we are new at something we tend to be slow, even if the end resault happens to be spectacular we may not be able to sell it at any kind of profit.

So my advice is: If you want to make a doll, make it for the sake of making it and for having it, not for selling it. If it does sell, that's a nice bonus.
Worry about marketing and profit for your second or third project.

 

I think that sounds like a very good plan. It's an amazing feeling the first time you hold a doll you made all by yourself in your hands. And, while it can also be a little bit scary, it's amazing to put a doll you made into somebody elses hands to see what they will do with it as well.
Once you've gone through the process once you will know a lot more about if you want to make dolls for sale or not and have a much better idea of what sort of costs are involved, what timeline to expect etc.

Best of luck with your projects!