1. When do I know when the holder or writer will exercise for a physical delivery or cash settlement option?
It is almost never right for a call owner to exercise early - unless the stock is paying a large dividend and the option is deep in the money. Then it's often correct to exercise one day BEFORE the stock trades ex-dividend.
Puts are exercised early, but only when they are very deep in the money. The put owner who exercises loses money if the stock rallies above the strike price, so the exerciser must be fairly sure that is not going to happen.
You can never know with certainty. The option owner has the right to exercise any time prior to expiration. The chances of being assigned early are very high ONLY WHEN:
a) A call option has a delta of 100 (99 is not good enough) AND the bid price is less than or equals the option's intrinsic value (the amount by which the stock price exceeds the strike price).
b) A put option is deep in the money and the bid price is less than it's intrinsic value (the amount by which the stock price is below the strike price).
2. Can a Spread help in determining when the excercise occurs ?
NO. It makes zero difference. The person who exercises the option has no idea what your position is. The person who is assigned an exercise notice is selected randomly, and thus, your position does not matter.