I had exactly the same gearing on my CAAD5 and was finding 39/29 a bit OTT for the steep climbs that I often encounter in this area. The first change was to get hold of some 12-30 cassettes. I'm not sure if Campagnolo still make them, but the 30 gives only a 3.4% reduction vs the 29 anyway so I wouldn't worry too much about that.
I discovered that my 10-speed rear shifter is quite happy working with a triple chainset so I bought
THIS ONE from Spa cycles. My rear mech had enough capacity to work with the change as well. I fitted an Ultegra bottom bracket to suit the new chainset.
I went for the 48/38/28 chainset so my bottom gear is now 28/30, more than 30% lower. It makes all the difference on the steep stuff. My top gear is very slightly lower, but no problem - I don't generally ride around at 50+ kph (except downhill) and I can always freewheel when I start spinning out.
My front mech didn't quite move far enough to shift to the 3rd ring because a metal tab pushed up against the seat tube. I managed to file enough off to overcome the problem.
When the middle ring wore out I replaced it with a 36. That is really nice with a 12-30 cassette. I can stay on the middle ring most of the time and the changes between the rings feel better spaced.
My 'triplised' bike...
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