IMO I'd just put some more money in (if possible) and opt for the potenza crankset with compact gearing. 50-34 with anything on the back is more than enough for practically all terrain (as you'll never really spin out 50-11) and the compact will give you wayyyy more options for future riding. You'll be able to have plenty of gearing options from the get- go and can use smaller cassettes with less 'gappy gears' whilst keeping a good climbing cadence. Your front derailleur setup will work best in this way, the aesthetics will be better and the cranks will probably have a better resale value (and more of a reuseability factor) in the future. If the centaur crank arms are not the best length for you (IDK if they are), then you can choose the potenza ones personally to fit you.
Best to pay once for a product that works perfectly than pay twice for one that doesn't (as I've found when getting handlebars that were too wide when I was too cheap to pay an extra 15$!).
Discuss light weight issues concerning road bikes & parts.