You wouldn't cut 1/4" all at once
Love to see him do that with a 1x6 piece of maple with a 1/4" cut. There seems to be no limit of YouTube videos by folks that shouldn't be giving advice.
I would have no problem cutting the tenon on one side using a blade height of 1/8" with a flat tooth rip blade.
The width is not really relevant in my opinion.
To your point about You Tubers giving advice, this individual is either an Editor or Contributor to Popular Woodworking Magazine, which takes him out of the "idiot" category of youtubers.
There is not a whole lot that can go wrong using that method to make a rabbet on the end of a board 1/4" X 1/4" .... I think I shall go make one myself.
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
Last edited by woodnthings; 02-15-2015 at 02:28 PM.