Hi Mikkel,
Getting late here as well, but as you mention yourself, you need to do a constant AoA (not pitch) approach do tests in ground effect. Also you need to separate lift, drag and pitching moments as they are all are different effects. Jan did a lot of tests and was OK with what we ended up with in XP 11.1. AoA will decrease as you get close to ground, so if you do it right you will need to trim up all the way down to maintain the AoA, and in theory you will make a very smooth landing in the end
We did a lot of testing, and so did others, so I don't expect you to find anything... . The pitching moment is a tad on the high side, but austin disagreed.
M