what about a Ladder on Both sides ?
Index Stays with out any Movement : 4700 CE sold and 4800 PE sold will give profit
Index Moves positive towards 5000 : 4800 PE sold, 4900 CE long will give profit. 4700 CE sold + 4800 CE long will act as a spread, so loss is limited.
Index Moves negative towards 4500 : 4700 CE, Buy 4600 PE long will give profit. 4800 PE sold + Buy 4700 PE long will act as a spread, so loss is limited.
I welcome more analysis please