I’m pleased to see that, despite the brand new tools ( most of mine have seen more than one user out) the author is using an engineers square in favour of the traditional woodworkers type that always go out of true. They are much better.
In latter times I favour Japanese saws for this type of work, instead of the European type – purely because (and I know it’s controversial) they are better quality and easier to use. Also they produce a much finer cut, once you get accustomed to the pull stroke. There is no excess kerf and they produce a better fit. It’s a matter of preference, but they are good.
There was an excellent video available in the UK some years ago by the late Jim Kingshot on cutting hand tennons. It contrasted the various types of tools and methods, including the Japanese, of which Jim was a great advocate. He also did one on hand dovetails in the same series.
Well said, I have a japanise saw and love it. Got it for christmas. I always cut tennons on the tablesaw - see my version of the guide on my website. I've also cut tennons using the japanise saw - with good results.