I was confused by your choice of words. "Der leech telltale sindt absorpt" will go into our sailing dictionary now (my excuses for "radbrechen" your language)
I am glad an aerodynamist have the same view on leech telltales. We had a hard discussion with Rick White amongst others some time ago who advocated dropping leech telltales and going by the telltales at max draft or thereabout. Simple is fast, but that was a bit too simple I think.
Would you care to guesstimate how large the difference could be between sailing with a streaming telltale at max draft and the section aft of that stalling, vs. sailing with telltales at max draft(or in front of max draft) and the leech streaming?