I dont know. You'll need to lump on Sam and bet small on the outsiders but I cant be working that all out. As for the laying, I wouldn't know where to start.
no its to do with Backing and LAYING together on the same market, at different times.
it can get complicated and takes a good while to get used to it, and recognise when to trade at the best times on the market.
ive been on betfair for a good while now, its taken a while but once you get there, there is some great oppertunities available