Raron

I can't be bothered to read all the posts where people are missing the point (or making good ones!) But to answer your question

Yes, its fine what you are doing, this side of the pond its common
You leave out the 'soft' switch as its not needed. The Sensor switch will power up the Rx just fine.
The system is still redundant as the PB switch is a twin supply redundant switch-with two regulators!
What the switch gives you is what you want it regulates the Rx and servo voltage to 5.9v-perfect for all types and makes of servo.
Yes the Powersafe Rx will take more current than the Sensor switch offers, but in most sports models its plenty. If you need more then use a Gemini II.

PB even do adapter leads that will allow to connect up the Rx/switch-regulator

Dave

Dave