Why can't you simply keep it in Mode A (default) and plug the servos in as shown above? You can simply use a normal servo "Y" to connect in the battery?
No need for decoders, etc. then.
Also, the nomenclature can be confusing.
The R7006SB RX is a 6-channel receiver, but using S.Bus it can do the max number of channels your transmitter can do.
The R700*SB RX is an 8-channel receiver, but using S.Bus it can do the max number of channels your transmitter can do.