Well, I can't help you with your frustration, but I can explain about the sun power.
In ArchiCAD 10, they finally have it adjusted correctly.
If you set the PhotoRendering Setting Sun to 100% and the ArchiCAD Built-in Sun Power to 100, and ambient to 100 in both, you SHOULD get a correctly exposed rendering.
Additional factors that affect these reliable settings - for scenes of "nominal" reflectance - include the magical "Undersun", additional energy from a SkyObject, and other light sources.
What you need for scenes of low reflectance or narrow windows and such, is , once you've put the sun to 100 in the Sun Dialog and it lacks brightness, you use the Multiplication factor provided by increasing that figure beyond 100 %.
After LightWorks in ArchiCAD was published, I went on the road and gave a seminar around a few places. The sun power thing was very confusing to many. I've included a few paragraphs that clarify the dialog box relationships in the upcoming ArchiCAD 10 supplement to my book, available only to registered owners of "LightWorks in ArchiCAD."
Attached is a basic rendering with ArchiCAD and LightWorks set to the 100 values throughout. with soft shadows from a realistic sun.
You'll see the shaded boards near the soffit are a bit "Crumbly." This is due to inadequate samples.