Hi folks. I'm about to hang speakers on the walls of my new living room. I've wired cables for centre-rear and surround left/right but for now I'm only going to use rear left/right (in addition to front centre and front L/R, of course). I'm using Wharfedale/NXT flat panel speakers as 'make do' equipment for now, but am thinking of replacing them better later on. How high off the ground should I be mounting the flat panel speakers?