I'm thinking about a few answers to your questions, but you still have not answered my questions to you yet? The reason I ask them is to find out your experience level and how you work. It is about impossible to answer the questions otherwise.
As far as the ring goes. Well you are going to do an important advanced magical operation with a powerful spirit. Would you want the ring to be out of paper or metal? Silver is not that expensive and is very easy to come by.
I am presently working with a friend of mine who makes rings to put some out (since the only other site that does made me an Enochian ring, charged me way too much and the thing came crooked!!). Contructing the Solomonic ring yourself wouldn't be that difficult with some silver, some silver solder (or jewlery glue if you are not that good with solder) some tin snips, a file, and a scriber (IMG:
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Btw, where are you getting the parchment? I have found "parchment" in the form of drum heads, but that is about it. I haven't found proper parchment for years. I tend to use raw leather, metal or other supplies instead.
Athena