I think, you are not addressing only 1 side of the coin ie. profit side of it. Try to look at other side too. Yes, you can buy 6 lots of options in money that u will put as margin for 1 nifty future, but that also increases your risk profile. With 6 lots in hand, and full capital invested in 1 position, I am sure, you would be watching DOW whole night and praying that nifty shd not gap open against your position and take away 50 to 60% of your acct.
IMO, Trading is game of statistics, probability, risk management and psychology. Hence trader need to address all of them to get consistent results.
Regarding trading ITM/ otm options, It depends on your strategy and market conditions.
If you can catch the direction right, then OTM option give better reward (they have higher gamma). If market stays sideway, then ITM option might save you, but OTM will keep loosing premium. And if market goes against you, then ITM will loose lot more then OTM cause they have higher Delta value. (I am assuming that you understand options greeks, else it is worth spending time to know them. Specailly if you are serious about option trading).
In my observation, people do not give enough importance to market condition before selecting option position. IMO, all strategies work under some market conditions and all of them fail in some other mkt conditions. Hence it is important to know the best time to use A strategy. As a trader, we need to address that while developing our trading system.
Hope this helps.
Happy Trading