I don't think going with higher rated outlets (duplex recepticals) is a great idea as in my opinion you should run the same as what the wire is rated for. Usually 20a outlets have a unique plug in so appliances with lots of draw can only be plugged into the rated recepticals. You certainly won't hurt the duplex recepticals but the wiring could get hot before the 15a breaker trips. Just my humble opinion and everoyone has one.
Tom Marty
__________________
|