I got out my copy of Healing Lyme to find the directions for the eleuthero. It is on pages 136-137 in my copy of the book.
I would go ahead and try to do what he says. The Russian dosage he talks about uses a 1:1 ratio. The Herb Pharm exceeds the Russian method and goes 2:1. You could try the 2:1 method. If it absolutely DOES NOT cover the herb, you could double the liquid and you would have the Russian-strength. If you do 1:1, after straining or pressing, you could either allow half the liquid to evaporate or double the dose if you want the Herb Pharm dose, or you could just go with the Russian dosage based on the 1:1 ratio.
Stephen seems to think the Russian method is fine, but then suggests Herb Pharm, which is double-strength. I would think anywhere between the two would be fine. Whichever ratio you do, you can adjust the dose to get the same medicinal value as the Russian or the Herb Pharm.
Hope this helps.