Yamaha 1300 Tourer - Yamaha 1300 Tourer Fansite

I am thinking of adding true dual exhaust to my '07 v-star 1300. It looks to me like the O2 sensor on the stock 2-into-1 exhaust is located where the two pipes join so I assume it just reads an average between the two cylinders? With the true duals the O2 sensor will have to be on the rear cylinder pipe. Other bikes are doing this and claim no problems. Is there any danger or potential bad side affects from reading only the rear cylinder? I really don't want to buy any kind of power commander to get two sensors and all that, unless there are bad side affects (poor performance, fuel mileage, etc. or worse). Any experiance and/or advice is greatly appreciated! Thank you in advance,

MB