G'day Mate,
You have invested in a good 6 channel computer radio, USE IT, select flapperon wing, plug your right aileron servo into "ail" channel, & your left aileron servo into "aux1", & bingo it is done.
You will need to "inhibit" the flap switch.
You have to set servo direction, travel, & subtrim, but you can also fine tune it as required.
Read your manual for these settings.
IMHO use Y harness if you are lazy.