JYB jewels is great, and ENV moissy is definitely something I'd purchase if I were in the market looking for custom shapes, good quality, etc. Don't hesitate to write her though etsy for questions either--I was considering an antique cushion cut and she was great about answering questions, providing pics, etc.
I know this post is a bit old, but I wanted to chime in and say that I just placed an order for a 6mm ACC from JYB to replace the center stone of my ering! It's been five years since I originally sought out this forum looking for information on moissanite, and I feel like I've come full circle!
So far Jules has been super helpful and prompt. I'll post a review when my reset is done (in a couple months--custom cutting takes several weeks), and I hope others who purchase from her will, too!