John.
I've actually not used Astra Image in a while. I didn't like the way it performed histogram stretching when converting to grey scale.
I also have the trial version. I wasn't even aware it was possible to adjust the resolution when using Prnt Scrn
When I used to use it...all I did was 1) Split colour panes 2) perform LR decon 3) recombine RGB. Then I'd take it into PS for final touches.
Does that 3-step process in Astra Image sound the same as yours?