I would suggest, if you are actually really interested in the stuff, making some drawings, as carefully as possible. Start by sketching, then work out the arrangement of parts, then work out some scaled drawings to suit. Typically you would want to scale them up at a convenient factor, like two time life size, or in the case of small parts, ten times. Ten times is nice because you can read the dimensions directly by measuring and dropping a decimal place. Any errors in measuring off the drawing are reduced by the same factor of ten when converted to real size, too.
If you dig around the web, you should be able to find a couple sets of shogun blueprint drawings out there. I know that at least one set is posted of the Winchester Model 21, which has ejectors, I think. Anyways, it is an interesting idea, if a bit impractical, but we do impractical things all the time, if we enjoy doing them.
Another useful location to search, if you are good with dealing with drawings (not everyone is), is the US Patent Office website, where you can search for patents and improvements related to Ejectors for Firearms, and see what ideas other folks had that they thought were worth a Patent application.
At worst, you will learn a fair bit about how these systems and mechanisms work. How can that be a bad thing?
Cheers
Trev