The thing about this is that there aren't really any points of mixup: Anyone who blocks this once will likely block it every time. It can also be blocked low, which is weak because most decent players, by default, block low.
You need to
a) incorporate your overhead
b) incorporate jabs
c) incorporate grabs (really ties in with b)
Then, find out what your points of mixup are (IE where you have the option to use a high/low or grab/low or whatever) and learn how to move them around your blockstring.
In terms of opening people up, the Japanese community has demonstrated pretty clearly that 2A/5A pressure is far more effective than any other blockstring you can cook up (for most characters, anyway). You should really take that into consideration with pressuring people.