I struggle some with this as well. I can get mediocre results with basic stuff and IR's in Sound Designer but I really am sure I can get better results. Problem is time is spread so thing that I haven't had the proper time to really sit down and learn SD'r to the extreme. I have also seen some amazing IR's available for SD'r but they are so expensive that you can practically buy Altiverb for the same cost. And I know that Vienna has one coming as well that's rumor'd to be in the vienna suite. Problem with that again is I would only be able to afford to either buy the plug-ins, or another set of instruments. Not both.
I tell you what would really help is a user matrix area. A dedicated place where we can all upload our Vienna settings files to help people. Because I would love to try to get some settings from some of the demo's and or tutorials but none of them are using VE3 network setup so my macbookpro can't handle loading any of them. They simply overpower my laptop trying to load all those instruments locally as compared to on my VE3 64-bit machine. I have read over time that this idea of a user file share area is been thought about but I am actually quite shocked it's taking so long to have one up. I can't even begin to tell you how much having the ability to learn from Guy and other people through some of their settings files would help me, as well as motivate me. I work 2 jobs so I don't have the amount of time to spend on this as others do and would benefit hugely from their knowledge.
If you do end up getting good results or help on this be sure to let us know because I have to decide on whether to buy more instruments, or a reverb. And with the right information SD'r probably would suffice for what I am doing for now and would allow me to buy more instruments under the current promotion.
Maestro2be