There is a thread in the archives somewhere of a member that had too many large golden shiners and was keeping records of removing them from his pond.
I believe he was both fishing and trapping.
Personally, I have never caught a GSH, so I am of no help at all to you. However, my foggy recollection is that there was lots of good advice in that thread.
I do like your careful management of your small pond. However, that certainly requires accurate sampling of all of your pond denizens.
Good luck finding your shiners!