After re-pointing the dish to 28.2, and before tightening all nuts and bolts, I wanted to check the (reasonable) CM feedhorn + LNB combinations I had in my toolbox vs the Inverto Black Ultra.
Thus I tested (in a span of about 10 minutes) the following:
The only major conlusion I have is that the Invacom Quattro + CM feedhorn is about as good as the Black Ultra for 10773H.
Or the other way around, whichever you prefer.
I have not tested 2G vs 2E/F, and there's no cross-polarisation checking etc.