Perhaps you may check out bespoke gem...
Doug has some beautiful pink amethyst and tourmaline rough that he may cut into a 8x6 oval...I'm not sure if he has any morganite though...
Jason Brim has a lovely, well cut light pink spinel that is within the realm for an 8x6 setting on FaceBook for sale. I have bought several things from him and I've always been happy. He's asking $300 which is reasonable. Check it out.