Can't explain your group skin, maybe another addon is causing a conflict?
With your raid skin, set the Row and Column spacers to 0 on the
Skins Frames Bars General tab
and set the background bar outline to 0 on the
Skins Frames Bars Colours tab
.
Try importing some of the extra skins, you can do this directly in game by selecting an extra skin on the Import skins tab and then click import.
To view extra skins before importing, there are
images in the gallery here
Finally, when you have the skin as you want, I suggest exporting it and saving it in something like dropbox.