So I have a 31.7 deda bar + 130mm stem. I need to get a longer stem(at least 150mm). Those are pretty much impossible to get in anything above 140mm (those are hard to find. I got a 140mm deda newton and it was a piece of junk).

So I'd like to switch to 26.0mm clamp and go with Oval Concepts ( stem.

I weigh about 190lb and have the longest Leader frame (590mm top tube).

2 Questions:
a) I have a carbon steerer, is that going to be a problem with a different size stem..especially one in the link?
b) I found some cheap cf bars. Is there any reason to not go for cf in 26.0mm clamp size? are what I'm thinking of.

It's either that or easton ea70

I like to climb hills. Which bars will have more flex?
Is there any trouble with pairing al stems & cf bars?