Assuming your two subwoofers are getting separate left and right channel signals treat them like extensions of your main speakers by placing them next to, but forward of, your main speakers.
The listening position method is meant for single sub placement and it can be very successful. Unfortunately, those locations can be obtrusive to multi use rooms. Still, if you have the time the procedure can give you another character aspect of your room.
If your subs lack digital signal processing then a product such as DSpeaker may be of great benefit to better integrate your subwoofers into your room and system.
The listening position method is meant for single sub placement and it can be very successful. Unfortunately, those locations can be obtrusive to multi use rooms. Still, if you have the time the procedure can give you another character aspect of your room.
If your subs lack digital signal processing then a product such as DSpeaker may be of great benefit to better integrate your subwoofers into your room and system.