I don't think it's that complicated to get things square but, as others have said, what you need to satisfy you depends on the level of "squareness" you desire. I don't currently have a square that is guaranteed like the Woodpecker's MFT square would be and, so far, haven't ordered it (although it certainly looks cool). It just isn't necessary. I've used several different squares in my shop, all with the same result. I have a couple of small engineer's squares, a cheap triangle, a plastic drafting triangle, and a fold-up square (which was allegedly more accurate than my other tools). I get the same result with all of them. I also have dogs for the MFT (3 sets for other reasons). I've squared using those also. I still get the same end result. Peter Halle has a great video on squaring with dogs. It works. If the end result fits in your project or, when assembled, looks the way you intended, it's right, square, and the right size.
It would be nice if there was a fixed reference point on the MFT where the fence would just sit and be automatically square using the holes and you would just need to square up the guide rail, but, in the end, all the methods I've seen work. It makes some happy to have a square, like the Woodpecker's square, that is never in question. I admit that, in my mind, there is some finality about that concept, but I definitely have survived without that square.
