I do have that setup in my Acuracy Bipe,

Wing Type set to 4 Ail 2 Flap
Stab 2 stab

I programmed all the servos to respond to its Function channel, it does not matter if you program a servo to a channel, if connected to a regular channel it will work as a regular servo, as on every start up the servo identifies the signal it receives and selects itself the method of operation.

ch1 Ail
ch2 Ail2
ch3 Ail 3
ch4 Ail 4
Ch5 Rudd Regular Ch
Ch6Elev
Ch7Elev2
Ch8 Ign Regular Ch
Ch9 Thr

I have each wing with both ser with one connector (soldered instead of Y), Then a Y to connect both wings
It works really well, so I cannot tell any difference as with a regular setup, but saved weight in extra leads not being needed.

Regards

Alejandro