I don't think it's so much skipped steps -- everyone's steps are different! You just make new steps wherever you need them. ;u; I kept finding that I hadn't left enough room for my word balloons in my art, so that's why I started putting all the text in before sketching in the art!
The finished page I linked to up there actually does have different sized fonts! The lines "could you not find the church" "aw, come on" and "I think I did pretty well" are all based on pt11 font, whereas the rest of the dialogue is based on pt13! (I digitally hand letter but use the text tool as a guide so they basically have a font size, haha). I use that sliiiightly smaller font size all the time for little asides in the dialogue -- for me, it's kinda a stylistic thing!
But if you're talking about more of a "oops this dialogue won't fit so I'll make the font smaller" scenario, I personally only use that as a last resort. If I have a line that I reeeeaaallly feel like will lose some impact if I shorten it or break it up, and knocking it down to pt12 or pt11 will make it fit, then sure! One point smaller usually isn't noticeable anyway. (if I go any smaller than 10 pt, though, for the size and font I work with, my letters start getting too small)
But I think if there's a balloon full of talking and the font gets noticeably smaller to fit it all in, that looks kinda bad. It's like how your eyes automatically skip past fine print -- as a reader, you'll want to skim over that balloon. So I think if at all possible, it's better to break it up into multiple balloons and spread it out, and try to avoid having characters talk and talk and talk in one long balloon!
(I hope this answers the question but if I misunderstood please feel free to ask again!!)