Just seems like a lot of risk to take on to earn $1,000 in 2 months. Many of us can earn that taking an ES position with less margin.
The maximum profit is only made if held to expiration so if you close this position sooner as you are hinting then your profit will be less than $1,400 so your expected return on this trade is much less than you are stating. You cannot say in one breath you will not hold it until expiration and then use the return value as though the maximum profit was earned.
It is not that GOOG has a small probability to make a 20% swing, it is you are taking on a large amount of risk to make probably $1,000 at best if you close well in advance of expiration.
Assuming margin is calculated on the larger side of the IC ($30) then your margin is $30,000 minus the credit of $1,400 = $28,600 maximum risk. Your profit will be about $1,000 since you claim you will not hold to expiration so your possible return is $1000/$28600 = 3.5% in maybe 2 months since you need theta to kick in. This spread will not be worth $1,000 in early January, it will take more decay and time to get there. So since you claim you will not hold to expiration, the return is not the maximum but less. Especially given the fact the options have wide spreads and you cannot guarantee a fill at the midpoint.