Mr Graham,
Much of the above is very good information and I second the credentials of Aaron Little.
Here is a link to the W Ellis Brown book on this subject.

The book will answer most of your questions including which calibers Ellis has found to be satisfactory for conversion to double rifles.
This is also one of the best prices for the book. You should find the book enjoyable read and very informative.

Edited by crs (11/17/19 09:21 AM)
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