Yes, I do it the same way. For example: If I need a pad sound, I check the pad category on my TI and browse through the patches. If I find something useful and the sound is good enough, the sound stays untouched. But often I have to tweak a little bit, some filter and envelope changes etc.
When there is nothing useful to find, I have to tweak the whole sound.
I think it's not the best way to create every sound from the beginning. Browsing through the patches can safe much work and give you good ideas what is possible with the Virus.
But I agree with gtrance: "Synths are meant to be tweaked" and not ONLY for using preset sounds!!!
This is for all guys who want to understand how to tweak:
http://www.dvd-lernkurs.de/audiobear...tml?Itemid=169
Sorry, but this DVD is only in german. I couldn't find any english versions.