my viennas are 100% vienna malt
well, a couple oz's of carafa malt to darken it to the approp color. vienna itself isn't dark enough believe it or not.
as to the "too much vienna" element; just add more hops balance it out. A Vienna Lager is truly one of the styles that should be 50/50 malt/hop perfect balance.
On a side note, I have seen written that modern "vienna" malt is actually pils and munich malts combined. I would like to know the truth of this, or at least which companies to use for "true Vienna" malt.