the long-arm quilter will tell you how to prepare your quilt- it is loaded one piece at a time-so definitly DO NOT BASTE IT TOGETHER! the backing and batting need to be larger than the top and each long-armer has her own policies on how much larger (i ask for 5" all the way around- meaning if the top measures 60"x70" the batting & backing should be 70" x 80" ...or larger)
there is a wide range of pricing- some charge by the square inch=some by the pattern= some by the over-all measurements---call the long-armer you are interested in using (or if doing it long distance start communicating) and make sure you like the type of quilting she/he does- everyone has their own (style) some use panto's, some free hand everything- some have templates...and everyone has their own fees, turn around time, and policies.