I have not seen a reference to Klages since the nineties, but it was very popular when I started to brew. I still see references to Harrington being used in craft brewing, so it must be still available on a least a limited basis. What made Harrington so popular was how quickly it modified, which improved malt house throughput.
That is what I remember as well with American 2-row being 120 Lintner. That is still more than enough to convert at least 30% non-malted cereal grain. However, I only 20% corn in my Pre-Pro Pils, either corn grits with a cereal mash in addition to a main mash ending in a combined mash or flaked maize with a single infusion mash.
I am fan of Cluster. Denny and Drew posted my Anglo-American Bitter on the Experimental Brewing site a few years ago. Used correctly, Cluster is a lot like Galena in that it is pretty neutral as a bittering hop. It is also one the most stable bittering hops one can buy.
The first time I had Jeff Renter’s “Your Father’s Mustache” at our club meeting, I had to tell him that the flavor was what I remembered from stolen sips of beer from Dad and Grampa. He smiled, and said “Cluster hops”.
I use Cluster early, then Saaz, or Mittelfrüh, or an American derivative late. Cluster is just part of it, for me.
I heard a while back that there are many cluster hops out there, early harvest, mid harvest and late harvest cluster, as well as Ivanhoe cluster. What was told to me is that Cluster was a name for almost ANY hop that was grown commercially in North America, and that there might be many different and unique “Cluster” hops out there.
From Ron Pattinson you can learn that EKG is a catch-all for whatever they are growing in Kent. Usually there is Holding in the name.
Hallertau? You can buy Hallertau hops. Those are whatever from the Hallertau Region, often Hallertau Gold. Always look for the region and variety. Hallertau Mittelfrüh, Hallertau Perle, Hallertau Tradion, and so on.
Edit, I’ve had good results with whole Cluster from Hops Direct.