Iron Condor is market neutral strategy so anytime should be best time. Why is it the first day of the series ? Does option pricing depend on what day of the series or does it depend on factors like volatility, remaining life, probablity of underlying reaching the strike price during remaining life ?
IMO, if you right 400+ points otm when 1 week is left, than u are taking a chance of almost 98% in your favour. What is the probabilty that nifty will move by 400 points in 1 week.. Becuase it is low risk, high certainty of keeping the money, your rewards will also be less.
But if you right the same 400 points OTM with 4 weeks to left, the odds are much higher that nifty might make a 400 points move in 4 weeks and hit your strike level. Hence risk is higher, low certainty of keeping money hence rewards will be high.
If you are giving the life of 8weeks for 400 points move than odds will be even less in your favour. Bottomline, each of this scenario has different probablity factor attached to it and hence your rewards are also different.
Better to consider typical move of nifty in remaining life and then construct iron condor beyond the reach of nifty. Depending on mkt sentiment, you can think of skewing it a bit on bullish or berarish side.. eg - if current trend of nifty is down, than create call spread a bit closer to spot, and create put a bit farther away to increase return.
Beauty of IC is that one leg is guranteed winner, and risk on second leg is limited hence you will not blow your account. If one can select strike price correctly than it is nice income generation strategy.
Hope this helps. All the best and happy trading.