QuickTime isn't a codec, it's a multimedia framework.
Basically, don't use QuickTime anything and you're good.
However, for best export quality you'll want those preview files to be as high quality as possible, preferably Uncompressed or something lossless. I like the UT codec, which works under AVI for Windows. On a Mac, not sure you can do it, as any lossless would use QT.