Understood, I just tried to show how small. The values were not measured but calculated, and indeed downwash is not linear so it's tricky and the known calculation methods are all approximations. But we're in the ballpark.

The examples were some I have at hand. The last example, the Integral pattern plane, has indeed 0.14 wing Cl at 100 ft/s (70 mph), so the downwash angle at the stab is about 0.9 degrees what I took from another example. Decalage is rather 0.94 degree in this example for zero stab Cl (if set up for that). Another counter-intuitive thing here?

There's no drive/thrust taken into account in these calculations. The wing downwash is part of a quite wide-ranging flow system, as was also shown in another thread where (shoe?) calculated the change in pressure at some distance (below the wing, IIRC). So even a T-tail is in (nearly) full downwash, even if not in propwash. And it's not in the turbulent wing wake that stems from the boundary layer (except in a deep stall where the stab may be blanketed).