I just went to covers and looked at the lines for the 6 books that they have live lines for. SIA always has good lines on dogs and in 6 of the 8 games for today that was the case, but for SF and FL they had the lowest lines on the board. Obviously they didn't want dog money on SF and FL.
The search for the holy grail. Hope you find it. The problem with SIA is their lines move so quickly based on a small amount of money. I remember when I used to play there, if you wanted the Bears at -6 for $500, sometimes, they would only let you play $316 for instance and then you would refresh the lines and it would be up to 6 1/2.
Check out the lines when they first go up before the impact of any wagers.
Just so there's no confusion on this, I'm using SIA to figure out the plays, then I go to the book with the best line on the game to actually make the bet.