Hi, Saji,
When u trade only Long in Options, it is Very Difficult to Hedging in overnight option trading because during big gap up/down, all following 4 would be against U
1.Directional Risk(Delta),2.Stock Price Change(Gama),3.Volatility Risk(Vega),4.Time Decay(Theta).
Now following are the solutions according to me to minimize Risk:-
1.Fighting against 1.Delta & 2.Gama
For overnight big gapup/down usual biggest risk is from 1.Delta & 2.Gamma
To neutralize Delta & 2.Gamma U can consider 3:1 or 4:1 position in Option & Future respectively.
For example when nifty future Closes near 4900 (say yesterday 4891.1)
Buy 1 lot nifty future against 3 or 4 lot bought 4900PE and Short Sell 1 lot nifty future against 3 or 4 lot bought 4900 CE.
2.Fighting against 3.Vega not advisable as it would be ur friend when u are in right direction with 'Long Option'.
3.Fighting against Time Decay: U can close ur position Weekly(Friday End) or B4 NSE Holiday and initiate Fresh Position next trading day. I use this strategy & this is very helpful also because big gap up/ down also happens @wk opening/after holiday.
Happy Trading.