Race the 1000 & 1650 the same day

I would like some input from people who have actually swum the 1000 & 1650 on the same day in a meet. It looks like there are people out there who do it seemingly successfully (by looking at their times) but I wonder if they regretted this decision a bit. Or trained specifically with that intent. The only thing I could think of to prep for this might be doubles in the pool once or twice a week. Or were they able to successfully nap between the events. See, I'd like to swim the 1000 at Nats but I'm basically shot to high heaven after that event anyways. I just barely meet the Qualifying time in both for my age group, so that's not a deterrent. So, I'm considering potentially "stupid" things. And I can't decide whether I should be talked into or out of doing both. What do you have for me? Advice? Warnings to heed? Help me fully inform my decision.