Unarmed self-defense is tricky. You can spend years learning things that are counterproductive to how your body moves and what actually happens in a physical conflict. You can also spend years learning skills that depend on youth. As you age, certain kicks, strikes and throws have less meaning because the body can't retain strength and elasticity. Keep it basic, keep it simple, and keep it repetitive.
The key to self-defense is working with your own leverages and fitness levels as well as simple repetitive practice. You practice basic combinations in a repetitive fashion much like you practice a musical scale.
This is the second type of block/deflection that John McSweeney taught. Added with that is a Ed Parker Kenpo technique where a deflection is continued with an outer block that can lead into to different types of arm bars or joint locks.