Would recommend reading the book "Bringing down the house"....
One of the few books I have ever read cover to cover in one session.....not much of an instruction manual but a basic story of the MIT students who teamed up to rack the casinos.....basically a number of counters placed throughout the room at different tables calling in whales to bet when the count of the deck reached a favorable percentage.....
tough to count 6 decks.....need to keep a running count based on the "plus and minus" as the cards come out....with six decks, if the cards are in your favor you have more time to exploit your advantage.....
more and more of those automatic shufflers out there that constantly shuffle the deck.....nowdays the deck is being recycled during play instead of being used up.....no point in counting a deck that never gets smaller.....