Man I responded to your questions DMRBG but lost it somehow.
Here goes again.
Not sure when the book will be out but it should be any time now. I know it was at the printers a few weeks ago. Steve is an honorable guy; no worries.
I think a half barrel would be fine for six small bluegills
I like the circular tanks because you can get a centripetal flow going that moves all settleable solids to the center drain.
BTW I love the cat. He looks like he wants you to pay attention to him or her. Tells us about the cat.