when i first started doing fades i did them as you say by bobing each color. basicly do the one color and rinse the parts off good and do the next color. no need to wait between colors.
this marker was done that way
this markers was done with a steper michine setup
sorry can't get the images to post for some reasonhttp://www.rainman229.com/images/web/anno/kevrm.jpg http://www.rainman229.com/images/web/anno/snowice1.jpg