Essentially the M is calculated by dividing your stack by the total of blinds and antes. You dont normally have antes in a sit and go so just combine the blinds and divide them into your stack. The resulting number is your M.
I can't stress this enough, but in tournaments when your MZone is critical, your only move is all in and you are hoping to get heads up with just one other player. Now in that sense, a random hand calculation is only useful in certain scenarios. For instance, if you are in late position and the blind players are reasonably tight and have a medium stack. You are the first to act as everyone else has folded, so your low Mzone forces you to go all in. There are 3 players left to act - the button, sb and bb. Since you were the first one in, their hands are truly random as they have not been able to act yet.
Ironically, plain english is exactly TJs problem with this new book. After just reviewing John Vorhaus new Killer Poker Book (online 2), TJs writing really put me to the test of patience. It was like going from a taste sensation provoking French cabernet, to a stale, warm American light beer.
The point in question is the comparison of single table sit and go tournaments to the final table of a multi table tournament. Howard says the sit and go tourneys train you for when you get to a multi-table tournament final table which you may know can be months in between appearances. He is right in the sense that that they are both tournaments and when someone gets eliminated, no one replaces that player and the table reduces in numbers. Its about there the similarities end.