I played around with things some more and found that the variability is coming from the ter rebuild and the ter size. One model I don't have to scale the ter up to get the desired results, however, I have to rebuild it with more points. In another model I have to scale it up and rebuild it. To complicate things more how many points you add in the rebuild affects things. Given all the different combinations of possible things going on, there is going to be a lot of variability, no way around it.

Found the problem. I tried rebuilding the suction and pressure side curves as well as the trailing edge radius (ter). I added roughly double the points to each and everything worked. I will update the screencasts on my youtube page in the coming days.

Update; Unfortunately, the above did not entirely fix the problems. Later on operations failed to create good geo. So I'm still going to have to play around and see what exactly causes so much variability.

I found the problem. If I rebuild most of the lines, arcs, and circles used throughout the entire modelling process everything works fine. I did not need to scale the ter up at all.

Latest pictures are available at; http://propdesign.weebly.com/screenshots.html

Latest screencasts are available at; http://www.youtube.com/user/propdesignsupport/