Post throttle vs Pre throttle

[ricekikr]

Is there a big difference between installing the meth nozzle pre vs post throttle?

I'm inclined to install it post throttle because there have been issues with it leaking into the throttle and messing up the TPS and Idle control. I understand that meth needs to be as far away from the throttle to provide the maximum cooling, but does it really make a big difference?

Does the checkvalve work well if installed post-throttle? Or will a solenoid be needed?