The fix I provided was ment for the problem that occurs when the website is displayed in a window that's about 980 pixels wide. Have you removed it from the functional stylesheet? I wasn't able to find the lines in the file.
The other two issues you mentioned aren't actually problems caused by the slideshow, they are the default behaviour of the slideshow.
As the slideshow will always try to fill up the entire width of the page, there needs to be CSS padding around the slideshow if you don't want it expanding to the full width of the container. Your 'screenshot' element in this case.
When the browser window is wider than around 980 pixels, there is CSS padding on the 'screenshot' element. However, this CSS padding is changed when the website is smaller than around 980 pixels.
The white area below the slideshow exists because the 'Shrink slideshow's height when width shrinks' setting is set to 'No' in your slideshow's settings. Because of this the slideshow's height is a fixed value.