I can't say that I completely understand what you're describing with the star pattern, so it's difficult to critique or praise.
I like the idea of two cameras pointed at different vertical orientations with overlap between the two. I think that'll set you up for great success.
I honestly don't know how good it will be for Photosynth, per se, but you might be interested to know what the planes that capture imagery for Bing Maps' Bird's Eye View photos do, if you aren't already aware.
There's a great video on Channel 9 that details their flight pattern, etc. here: http://channel9.msdn.com/posts/Mark+Brown/Behind-The-Maps-Flying-the-UltraCam/
Again, whether its appropriate for Photosynth or not, I don't know, as I'm sure that the Bird's Eye View imagery is placed in Virtual Earth|Bing Maps based on professionally recorded GPS and orientation data, rather than relying on photogrammetry, but their overlapping corridors of photos might work for Photosynth as well.