Hmm, I don't have a website or article, but I honestly suggest you just try and analyize the vertical format comics that you like. Take a look at the example you posted, and the differences between it and a traditional rectangular comic. Usually vertical comics are very spaced out, and take advantage of the the user's ability to scroll through quickly. This artist in particular uses large gapes between panels to disguise where the breaks in the pages are, and set up large images that can fit a mobile phone screen quite well.
In terms of actual size ratios and setting up your document, it can vary a lot, so I suggest maybe saving some to your computer and bring them up in the art program of your choice to take a look at what other artists are doing. You've kinda got to decide whether you'd like to size your comics to suit mobile devices or monitors too. I'm more used to setting up for print media, but I have done a few vertical comics before. The biggest difference I'd say is that with the vertical format you don't have to worry about having large scale documents that will eventually go to print. You can get away with only doing your comics in 72ppi if you'd like, but it never hurts to start at 300dpi resolution because you can always scale down. 
Hope that helps a little!
