There are multiple ways to look at this problem.
First, let's look at the area where the damage is. That part of the tire is at the edge of where the sidewall does all kinds of weird movement - which is why sidewalls aren't supposed to be repaired - the repairs just don't last.
But being at the edge of that means the repair MIGHT hold up if the stresses aren't too high.
And what would happen if the repair would fail? If you are at low speeds, then you'd have a flat tire. As the speed increases, it becomes more and more difficult to maintain the control of the car if the tire suddenly deflates. At the extreme end, we are talking about a rollover - very bad!!
So what speeds are the limits? Most folks in the know would say that high speed starts in the 35 to 50 mph range. My opinion is that this means if you do anything more that inner city travel, you have crossed into the high speed arena.
So how much risk are you willing to take? Remember that at the high end, we are talking about a severe crash.
Another part of the equation is what folks are willing to repair. This is clearly outside USTMA's (US Tire Manufacturers Association) guidelines for repair and many tire shops won't touch such a repair. There are shops that will do such a repair, but they just don't care about what happens. If there is an accident, they are planning that the lawsuit won't be against them - and most of the time they are right!
Personally, I don't like the odds here.