These formats are more digital drawn friendly than traditionally drawn friendly because of the fact that they are essentially a 'limitless canvas' that ends when you're ready to make it end.
But that does not mean it's impossible to make a vertical comic that is traditionally drawn, it just needs to be reformatted to fit the reading style, so you'll most likely be going through many similar steps taken by artists converting a page by page comic into a scrolling vertical comic (digital or traditionally drawn)
Try focusing on the panels instead of pages is the best I can give you for advice, as the idea for a vertical comic is to remove the constrict of a typical 'pages size' or 'page limitation', so the panels are what you're going to be working with, as with anything related to drawing the more you work on it the better understanding you'll have of them medium, you'll figure out what works and what doesn't. It's a learning process, always will be even for experienced artists =)
