>I have found whilst it takes a bit longer, I get better >results this way but only having the sensor up one spout >so to speak seems to me would not give a completely >accurate readout.

staffo - on these bikes there is a cross over pipe between the exhaust headers, the location of the (oxygen?) sensor in one pipe or the other probably doesn't matter much.
the exhaust gas should be fairly homogenous.
I suppose the most accurate way would be to have a port for a wide band O2 sensor welder onto each header. Probably not worthe the cost and effort unless you are racing.

05 speedmaster - 1100cc, 11:1 racing pistons, Carillo rods, thunderbike cams, ported and polished head, 2mm over intake and exhaust valves, Barnett kevlar clutch, scepter pipes, oversize manifolds, 45mm HSR's, TTP stage 4 firestarter