Good Point JackRab. That makes sense about the 1700, instead of 1690.
I guess the trade is really a protective trade if an atomic bomb goes off, and the Market drops to 1300 quickly (unlikely)...but if it did, I would be wiped out if trading unhedged.
Okay, so your main strategy is shorting far OTM, but do somewhat of a hedge by buying a shorter term one... that's better than outright short, smart move... most people would just do the outright and not bother with risk.
Definitely go with the 1700 calendar in that case, since with a move to 1300 you would still get to keep the credit. The 1700 cal spr is worth next to nothing with SPX far far away from the strike...
As I and others mentioned... worst case is expiry of the 45 day put at 1700 (or 1690 in your case).