I've noticed that when I select a patch I cannot seem to always get the 'variations' listed on the right. I usually select 'Roland VSC (GS Mode), then choose my main patch, then try the variations on the right, but often-times, I don't hear any difference, even when the listings on the right indicate that they are distinctly different sounds. Any advice on this? THanks.

Patch list has to match the synth. Can't use the extra sounds if the synth/soundcard doesn't support it.

That said, variations are often just that; variations. It may simply sustain longer, or only make a different timbre if you play the note hard(loud) from the keyboard .. or your synth may just be ignoring the command because it doesn't recognize it. That's why the support page has dozens of different patch maps for various synths. The one you refer to may just be an included GM list and your synth doesn't match it or support it.