Wow, this wedding dress gets more spectacular with every pattern stitch!
Best thing to do is to knit swatches for the various stitches with your yarn and needles. That way you can see the drape and laciness of the patterns. Once you have some good swatches in hand, you’ll be able to determine the number of sts/inch and then the number of sts for your measurements. You’ll also know how much ease you want with the dress.
It’s a big project with not much of a basic blueprint. You might want to find a dress pattern to use as a guide for your chosen stitch patterns.