I usually like to wait until about 1/3 of the tops have at least started to dry down before digging. Then cure in a warm dry place, out of direct sunlight until tops can be completely removed.

Steve

Check the flopping tops and see if the spot they are bending is actually soft and shrinking or if the tops are just flopping over due to heavy top growth.
If the 'neck' is still firm, you might consider waiting a little longer. There's no harm leaving the onions in the ground for a bit to cure unless you're expecting heavy rain.

-Mark

Thanks you two, this is very helpful. I think they are getting close, but I will give them more time to brown out.