This is all ab bit outside my level of expertise but I do think the overriding criteria should be driven by quality and effort applied.
How do I know if I'm actually a member of #steemsilvergold even though I use the tag to post and comment quite regularly?
Other bots just go from the bots "Following" list which is manually managed. Groups like Team Australia have a loose application process too (to make sure you are legit) before you get accepted, announced and put on the bot upvote lists.
We have a discord channel and i will update it to have a membership list that will be updated from the bot. I can do this manually every week. You can also check the bot following list. The bot picks from members that are active within the group and using the tag. I not sure if content is factored in atm.
Your a member man, and thanks for all the support. We are continuing with the quality post feature.