Hi Marc,
This is not a comprehensive description. But may help
http://www.astronomie.be/registax/re...usermanual.pdf
Page 38.
Everyone has their own favorite way of using the sliders and other settings.
It is generally accepted that "less is better than more" produces aesthetically more pleasing results, especially if further sharpening is done in other post processing. However it remains a personal and case by case decision.
If you include "Registax" in your google search you may have more luck.
Just two comments Re your Jupiter shots, which are not too bad BTW.
The 2x Barlow as you have stated will help (some use more ) to improve things (seeing permitting).
Try to keep the Histogram a bit fuller, these look a tad underdone.
And you could push the capture times out to 2min or more. Lots of people recomend a 90sec limit due to rotational blurring, but I have found that personally it has made no visible difference to push on a bit longer. Experiment with this if you wish. But I am sure that limits like this apply only to the better instruments, on nights of great seeing, and at large image scales. This enables a larger number of good frames to stack, and gives a lot more latitude with the wavelet settings
Whoops thats three comments
The whole stacking and processing aspect is really different to what I'm used to with DSOs. I'm a bit confused as to what wavelets sliders do, so I tweaked them until I got "something" I though looked right? 
Googled a bit on registar tutorials but none seem to give a definite answer on how to use them. Any pointers would be great. Thanks. 
