We have started with the key range 'ff00' and have about 260,000 work items from that.

eg (first 6 bytes of the 8 byte key):

start range - end range
ff 0 ff 0 ff ff - ff 0 fc fb 65 ff

next key range being loaded in will consist of 6,760,000 work items:
ff a dd dd 82 ff - ff a 75 44 eb ff