I'd make the same remark about Steven's case: if possible, don't create the indexes at all until you've loaded the table fully.
We considered this, however in some of our 12-hour partitions, there are upwards of 50 or 60 million rows near the end of the 12 hours so read performance gets bad on the current partition very quickly if there are no indexes.
It makes more sense for us to have ~1 hour's worth of reindexing afterwards during which read performance on that partition is "compromised".
