The shape of Signet rings

[Sheen]

Since playing with wax tubes, I now have a question. Are there any guidelines for statement rings/ signet style rings as to where the curve outward of the shank should start and how wide can it be before it's uncomfortable to wear. I have a round wax tube with an off centre hole. It's nice to follow the shape of the original round outline but maybe it is not a good idea to do so.