I have a 1982 RX7 with the 12a

I played around with the Nikki and want to make sure the AFR is correct.
I am installing a WB and was wondering (because rotary run hotter than your typical piston motor) where is the best place to locate the O2 sensor without worrying about having it get too hot?

 

Ive got mine somewhere near the back of the gearbox, mainly for packaging restraints, it was either there or straight off the turbo, and it is responsive enough - cant really notice any lag at all..
Supposed to mount them at the top of exhaust preferably, and if horizontal should be pointing down a bit to avoid moisture build up- that's what it said on the instructions.