Is there any real risk that somebody will exploit the design for significant commercial gain? Is the shortage of valve testers bad enough that it would be worth somebody's while setting up a production run? In both cases I rather think not. There are other designs already in the public domain, notably the RAT
http://www.triodeel.com/tester.htm I haven't noticed a rush to exploit them commercially.
I'm sure that Carl Glover (BVWS Bulletin editor) would be delighted to publish your design, even though you are not a member.