Lucky, the goal is FUEL LEVEL, right? Too much or too little the bike will not run correctly. I know we can agree on this.
By setting the float height, by the book, you are assuming you set them correct AND the floats are operating correctly. Nothing wrong with this method, but, once you put the bowls back on, the clear tube method is the only way to ensure the fuel level is correct.
We are just double checking our work here, nothing more.