I'm not sure if this is the "easy" way, or if it's 100% accurate, but:
I thought (I can't seem to find the thread here, but maybe it was the "dynamic pricing" one) that there seemed to be a correlation between the fare bucket and the number of miles required.

If that is/was true, you could maybe try searching for the flight with the lowest fare buckets, then doing another search for the exact flight and see what the miles is/are?

Although it may be "quicker" to just keep randomly searching the Delta calendar many times a day in incognito mode.