When I tie the waist tie, I like to tie it at a mid-rise height. The waist tie becomes the waistband. You could tie it high, mid-rise, or low depending on your fit preference.
Silk pins are a great choice for this fabric! Initially I made the mistake of using glass head pins and snagged the fabric in a few places. With ironing and wear, the snags are hidden but I wanted to note that tip.
I found pinning and laying out the fabric on a flat surface was helpful to prevent skewing the fabric. The drape is amazing when wearing the finished project but patience and care is helpful through the process of sewing.