Thanks David, Eddie, Alex, Frank & Kev
Can't wait for a filter wheel Alex, but this will do for the moment! For this one I took each and every image in TIF format that I had on my hard disk that was any good - no streaks, focus OK, no star trails, etc, etc and loaded them all into a folder. They came from several nights-worth of shooting and from the 350D in combination with both my C-8 and FS-102. They were all at full resolution (3456x2304). The ones I took from the ST-8i the other night were at 1530x1020.
Then groupled them into stacks of four images, and loaded these into a CS3 stack (files/scripts/load files into stack). For each of these stacks of four images I produced a second mean-stacked image and then adjusted shadow/highlight before saving it. From the 40-odd original images I was now down to 10 - plus the SBIG lights. I then divided these 10 into groups or 3,3 & 4 and did the same again. And again to get one final image that was looking pretty darn smooth. I then repeated the process yet one more time with the SBIG lights - and these resulted in a huge crop as the FOV was far smaller, of course. When these were stacked and merged the detail started to really pop. It's so hard not to try and over-process it.
Anyway - more to go yet. I'm still getting different results as I'm also trying to merge the larger groups into a better HDR image. I'll post it when I'm happy... LOL!