Welcome
Your quilt is unique enough that you might consider a professional appraisal. This gives both you, the maker and the buyer comfort knowing that each has made a good deal. A good place to start:
http://www.quiltappraisers.org/. Call or email one of the appraisers close to you - they often will do appraisals at quilt shows too, and you may be able to get a general appraisal by providing photos and details of the quilt. To me, it would be worth the appraisal fee!