Hi,
No problem! My favourite way is to load each instrument as a separate matrix within the same preset, so that a single mouse click immediately activates the correct instrument. Of course, I don't use an awful lot of instruments - it's pretty much always "loads of strings", "piano", "various woodwinds" or "brass". The alternative would be to load separate instances within the same vienna ensemble, but then, if you need to switch instruments, you need to solo the one instrument and mute the others (setting each to respond to omni midi channel) - which is more clicks and thus more that can go wrong. It's a bit silly - I have this massive midi channel switch pedal specifically for this purpose and obviously this would be easier, but I dislike carrying stuff around! (also, i do like the visual certainty).
Best,
Michiel