Thanks. So to summarize the responses there is no way to delay paying for a ticket except for the 24 hour hold feature.

Well then I wonder how this works from the TA side as they tell me that the specific seats are reserved for this and other trips, except for EK which will acknowledge the booking but not the exact seats until I pay for them. Further, they have always warned me that the airline may make a demand for payment at anytime. For example, if the flight is selling out in that fare class. Failing to pay at that time will cause the booking to disappear. I will have to research this further.