I have always obtained very good results with Rahr base malt. Granted, it was 2-row, not 6-row, but the beer produced was always very drinkable.
By the way, I prefer to make Pre-Prohibition lager with 2-row Harrington or Klages. There is no arguing that 6-row is traditional and that the addition of corn was to lower the overall protein level to that of European barley; thereby, making the final product more stable. It is just that I have made it with 2-row and 6-row and found that most of my friends and family prefer the 2-row version. Pre-Pro lager is to German and Czech lager, what Italian-American cooking is to Italian cooking (trust me, I grew up in an Italian-American family and I lived in Italy for a year and half when I was younger); namely, an adaption of technique to readily available ingredients. I believe that the more important ingredients are the hop bill. Back then, they only couple of varieties of hop from which to chose. Cluster evolved in the Hudson River valley as one or more crosses between hops brought by the Dutch and wild cultivars. However, Fuggle was used to a large extent as well (noble hops have never yielded well in the United States due our shorter photo period). I do not know how many people know it, but Anheuser-Bush sponsored the development of Willamette as a better yielding replacement for Fuggle.