Thanks, Michael!
I must admit that the low stand look perfect with the 7-55. The BV9 is big with a height of 122 cm, but the 7-55 w/BL7-4 is a massive 144 cm - I find the lower sitting picture on the BV9 compared to the 7-40 w/BL7-4 much more comfortable (have a rather low sofa, too), so the 7-55 with the low stand is spot on.
But I have tried a BL7-2 in an all ALT-setup for a few months, and when replaced with the BL7-4 the center channel became just as clear and well defined as the other speakers - no need to crank up the center volume to hear the dialogue anymore. They should have sold the BL7-6 with a center lense that became active in a surround setup.
Roger