Centennial would be good, but not really in the "classic" Pilsner taste. Use the Saaz, that's very traditional.
Be careful to not oxidize your beer when using that paint-strainer bag. You don't want your beer turning into something that tastes of wet cardboard.
So far the paint strainer bags have worked well. I initially thought I would strain the beer into the bag as it went from the primary to the secondary. However someone on this forum pointed out that the bag should be on the end of the racking cane that is placed into the primary. So now I rinse the bag in Star San and place it over the end of the racking cane and then place it into the primary to rack into the carboy. So far no off flavors.
I am going to rack it onto 1 oz of Saaz into a secondary carboy this weekend. It appears that the active fermentation has all but stopped based on the airlock. I brewed this six days ago but lost some of the liquid yeast when it kind of exploded when I opened it. I never used liquid yeast before and had not heard of this apparently common occurrence. In any event, it appears that enough yeast lived to start the fermentation it but won't know how effective it was until I take a hydrometer reading.
The brew I am working on is a kit from Adventures in Home brewing called Backyard Pilsner and has been reviewed to taste like that big beer from St Louis so I guess it is an American Pilsner. I know what's the point right? But I was looking for something that my wife might like as my taste runs more towards a hoppy IPA like Bells two hearted ale clone or Sierra Nevada.
Thanks for the advice.