Several in this area are 4 to 6 months from when you book in.
As a result, many register their quilts for a date and then make them accordingly.
For me, I don't care for that, as I don't want the pressure of the deadline.
And from the other perspective, once I have it finished, I want it LAQ ASAP too.
You're the one who has to make the decision as to how long you are willing to wait ... or whether you need to look for someone else.
Regardless, what is most important IMHO is that when they give you a date to start and finish, that they will meet that date and not delay it further.