5e3 - alternate speaker jack wiring?

[Ledvedder]

Are there alternate ways to wire the speaker jacks? I've added an impedance selector to my build. I'll be putting a 16 ohm speaker in the combo cab. I'd also like to additionally use a 16 ohm external cab at times. The way the standard wiring is, would it work OK with the impedance set to 8 ohms when I'm also using the external cab? Or would I wire the jacks differently?

[pdf64]

The 8ohm setting will be ideal in that scenario, ie 16ohm speakers plugged into each speaker socket.
As speaker sockets are (almost) universally connected in parallel, tip to tip, sleeve to sleeve.