Set it to one in and one out. Because the ECU program itself already doubles the value of the MAF. Now if you have a dual Pop installed with out the ECU upgrade then you want 1 in and 2out and "add". If you have a dual POP with twin MAFs then its 2in and 2out and then I would say AVG.
That the only thing that makes sense its not like Apexi would make there AFC to work with a JWT Dual Pop program :-)