Apis Hive uses 30%, there's no science behind it, just something that I thought seemed reasonable, so fairly subjective.

Personally I'm not sure about showing the accounts recieving delegations in your tool. It breaks your tool as you mentioned, but also some people delegate for upvotes, so the last thing you want is to help them advertise their services. If people were so desperate to find out, they can wallet snoop themselves.

And regarding your comment further up, I agree with you that the amount delegated could be removed to make the dashboard less crowded, or replace it with another metric. The % delegated says it all really.

I think the dashboard has a lot of potential and you can show all sorts of data. It's really getting this balance right so it won't take too long to return a query, and to show the major ones only.

The alternative, is perhaps do it in layers. The main dashboard to show the high level data, then you can click on say Hive, delegation, downvotes, comments etc to see more information