Yea those subs are very heavy, so we usually recommend going with the flip method of unpacking. Basically you open the first box, take out foam and corner reinforcements and flip the box over. Pull the outer box off, open the inner box and flip. I would try your configuration first of catre-cornering the two subs. The sub in the front would likely give you a good amount of deeper bass and the sub next to you would give you a better mid bass punch. That being said you are pretty close to the back wall, so you may still get great results by placing both subs in the front left and right corner. You can remove the feet and place the sub on a the sub pad. I recommend placing something like a towel under it to protect the finish of the sub a bit more, especially if the finish on the pad is heavily textured. One thing to make sure of is that if you remove the feet, make sure that there is no air leaking coming from the screw holes. If there is, you can try placing tape over it, or sealing it with silicone sealant. The pad is stated to decouple the sub from the floor so it won't matter either way.