Thanks, thats what im leaning towards too. I was just curious what people thought about the conversions, if I should have done anything different. Thanks for the feedback.
Darker one for sure. Even though you lose some detail with the increased contrast, the structure is simple enough to not suffer.
I would also recommend you consider cropping out the entire sky even at the cost of sacrificing part of the sturcture. It really is distracting. Of course the complete bridge without the sky would be better IMHO.