It depends on your palate, some likes their flavor as a shake n vape but some do prefer steeping. I would try it as a shake n vape first and also leave some to steep for a week or two. Try testing the flavors out everyday to figure out your sweet spot. Custard and cream usually takes 2 weeks or more for the flavor to fully develop but it depends on how you like it. Some recipe doesn't need steeping and some does. Also, if you like throat hit I prefer not to steep. The steep time on 0mg and 6mg nicotine is the same cause it's not the nicotine that requires steeping, It's the flavors that requires steeping so that it would blend together with the pg and vg. Try the VBIC and Apple pie as a shake n vape first if you don't like it try steeping for 3 days. For this mix I usually like it after 3 days but it also depends on which flavoring am I using in the recipe.