An update:
I have opted in favour of the Krzeszow sampleset after all. As I said, the Waltershausen was a very close 2nd (NB despite its status as a relatively old HW sampleset, it has aged really well), but the financial factor played a big role -- I'm still on HW version 4!
With that said, I must confess that I am very happy with the Krzeszow set for Hauptwerk. The sampling quality is exquisite; the organ can easily lead in full surround on a 16GB RAM (with front ranks at 20-bit and rear at 16-bit); all the multitude of individual foundation stops, as well as combinations, is a dream come true; and the chorus and/or semi-chorus combinations are also of top-notch quality, apt for a very pleasant reading of a multitude of works (not only Baroque).
Here is a recording I made, if you are interested: https://www.contrebombarde.com/concerthall/music/50304 (Noel Suisse by d'Aquin).
In short, I wholeheartedly approve of and recommend the Krzeszow sampleset.