Managing carbonation

Had a question regarding carbonation levels. I've been using the standard 5oz of priming sugar when I bottle and my brews have what I think is too much 'fizziness' especially with my porters and stouts which I don't really care for.

Would reducing the amount of priming sugar say by 1-2ozs make a difference or would I be screwing the pooch by doing that? Or are there other methods I'm not aware of for priming?

Thanks in advance

If your beers are young, I would say to leave them longer before you open them. I wait at least a month before opening a beer.

If that is not the issue, then decrease the priming sugar a bit.

I use 4 ounces for "regular" American style beers. I really like the idea of carbing to the style- and would suggest using a carbonation chart to make your beers more to style if you'd like that.
Here's an example:
British-style ales 1.5 - 2.0 Porter, stout 1.7 - 2.3
Belgian ales 1.9 - 2.4 European lagers 2.2 - 2.7
American ales & lagers 2.2 - 2.7 Lambic 2.4 - 2.8
Fruit lambic 3.0 - 4.5 German wheat beer 3.3 - 4.5

From BYO: http://byo.com/referenceguide/primingchart/

It tells you how much priming sugar (or how much co2 if you force carb) per style volumes of co2. So, for a porter, I'd do around 1.9 volumes of co2 to get a more appropriate carb level. That's about 2.75 ounces of priming sugar, if your beer is in the 65 degree temperature.

Thanks guys. Appreciate the help.