By flares, do you mean on the end of the burner pipes? If so, no I didn't. I've seen them on some others and understand that they apparently make the burners more efficient? If you did a design like this, I think you may be able to buy flares for the ends (Zoeller forge?).
I don't have a pyrometer, so I haven't found out what temps I'm getting to. That being said, after running both burners for 15 or 20 minutes I put on some farrier's rasps to anneal. In well under 5 minutes, they were both at non-magnetic. After checking the 2nd one on my magnet, I noticed the 1st was getting that really slick, watery look on its surface. Not sure what that means temp wise, but I was quick to turn the forge off at that point...
Good luck-lots of ideas out there and ways to make metal hot.
Jeremy