I have a 2009 Dahon Speed TR, This is a great bike that I was inspired to buy from reading the enthusiastic folder fanatics on this forum. My other bikes have drop bars. One of the things that keeps me from riding the Dahon for long miles is the lack of hand positions. A good compormise seems to be to put some trekking bars (butterfly bars) like these:

(image borrowed from Nashbar)

The raised center section is 1 inch dia. ( but less so to the left and right)

I have this kind of stem clamp on my Dahon:
(image borrowed from thorusa)

Which clamps a 1 inch diameter bar on the sides of the raised center section.
What to do?
Can you advise me on a bar that is uniform dia. across the clamp area? or other solution. Thx in advance.