I found a better method for using ImagesPlus, RegiStar and EasyHDR for doing HDR images and getting the full dynamic range of the target object.
Here is the first image. It is from only HA and O3 narrowband data taken with the Skywatcher 150mm F5. I will explain the method later.
Large image 2.25 MB
http://members.optusnet.com.au/~fmlee/M42_L.jpg
Bert