Notes from Elann.com regarding gauge and sizing:

This sample was knit in elann.com Peruvian Sierra Aran, but is easily adaptable to other yarns. The neck is not fully constructed with the cast-on stitches; it is constructed as you knit, as are the chest size and length, so any gauge will work. Simply choose a gauge that gives you the amount of drape, fluff, or density you want with the yarn you are using.

Sizing for lace garments is very fluid, and can be changed to suit at the blocking stage, keeping in mind that blocking will add more length than width. Size can also be changed as described in the knit-to-fit instructions below. If you knit-to-fit, simply increase or decrease your yarn requirements, according to the percentage you adjust the finished bust. e.g. if you were to make the bust 46” wide, rather than 42”, you would calculate that 46” is 10% wider than 42” (46 divided by 42 = 1.1), so you would need 10% more yarn – i.e. 14 balls rather than 12.