as I said I have been there and tried that with previous models from my Dehler. Some of them had as deep rudders as keel (almost 2 m) but it did not help. The Dehler 43 CWS rudder is also rather deep and big, but as you pointed out not to that extent, but mainly due to big ballast ratio and especially due to narrower aft section, is almost impossible to get it to round up.
We discussed this before Paulo and it is always good to give things a second thought . As I said before, boats with low ballast ratio and a lot of form stability can be very nice and fast in the right conditions (as was even my Beneteau Oceanis 40) but conditions are very seldom so stable as when these boats excel, or you need a very active crew on the sheets (and rail).
I agree, there are shades of heat also in hell
, but basically, twin rudders and planing hulls is what I am looking for.