Jack,
I made mine last year, it is the post towards the bottom of this thread:
http://www.pbsbac.co.uk/forums/index.php?showtopic=6356&hl=
I think the important thing is plenty of fresh water, nice'n'cold\well oxegenated and not too many live baits and no bleeders. I had an un obstructed barrel and I am sure no one told the fish about the ant-clockwise thing - they go up down accross and both ways!
I have a 360Rule pump and it only just has enough pressure to lift water in my boat (probably 4ft). I am looking at changing to an Attwood V500 Bilge Pump (has a head of 10m max and at 3.3ft 350gph and 6.6ft 200gph) cost - way under