The cross he skipped is pretty damn mandatory... I don't think any experienced stringer would string it like that, and even less leave it like that.
A good hit at that particular spot on the racket could probably cause the strings to break.
As for the knots, the "right" way of doing it for 4 knots is to have the bottom knots at b10 on each side, so 3 strings in the same hole (easily done if you enter your knot string and your cross string before tensionning the cross). b6 is ok, but it's a longer way from the last main to the knot and you have to get 2 strings to fit in b5, which can be quite tedious in some cases. It surely is not wrong to do it like that though.
I do it all the time - the MX pattern is terrible for breakages at the top of the mains.
In fact, it's a terrible pattern full stop, IMO.
Yup, I've had very good players break their strings there often, adding that cross does wonders.
I hate the pattern too, takes too much time (actually I hate all 1 piece patterns, hate dealing with all that string lol). But Kwun did find that this pattern was more playable, so it has to have a little something...
For most gamma machines with badminton top support, those crosses are no problem.
However, when I did not have those, I would tension the string with a curve. That string is only there to provide additional support to the mains at the top, so the resulting tension is not as important. Be careful though, because if your string breaks there, you'll want to shoot yourself, or just tie up without the extra cross :P
how do you deal with the 12oclock support? Do you just not care and tension the string with a curve?
On those occasions where the 12 support forces a bend, I just tell myself that the cross in question wouldn't even be there on most rackets, and go with the bend. On my machine, the deviation is no more than a quarter of an inch anyway - nothing to be overly concerned about.