I haven't read through all the responses but I have found this to be true of Smallies:
They are very different from one body of water to the next. (St. Lawrence, white drop shots and goby baits, must have current. Champlain, dark colors, C-Rig and can be found anywhere).
If they are present, you will know it fairly quickly. If you don't get one or a blow up soon after arriving at a spot, they probably aren't there
If you loose a big one (breaks off of throws the hook) the school will shut down for a long while.
They can be anywhere. 5lber out of 3ft in August OR the very next day, 5lbs down 80ft over 100ft while trolling for Salmon (this happens up here all the time).