Nice idea! But to be clear -- you have to screw the piece into the back of the speaker, yes? Not sure I'm ready to commit to that!
C'mon, be a man, you are going to drill into your house with ugly L brackets but won't drill a speaker, lol... Take a deep breath it will be fine... Do it rite, I marked everything with chalk pen first, measured it all out very precisely before I drilled, then I got my drill bit, put a peace of tap on the bit so I didn't predrill the hole too deep, then used some very nice stainless steel screws with ss washers, I put thick electric tape on the back of the mount {adds a tiny bit of cushion and stops the metal from touching the wood} {they sell the 2" electric tape at the depot}...
If you ever remove the mount, all you have is a couple holes that you fill with the screws... Its the back of the speaker... I did my buddies Ascend Horizon and that was also a $1550 center channel...
I guess you could do it with 3m double sided tape but I wouldnt....
Here is a non drill method for you...
Take your center mount they give you {that curved bottom piece} and the hangers I linked to you to a local machine shop and have them make you an L bracket out of sheet aluminum, so that hangs on the wall and the speaker sits on it, I know local guys around here would only charge around $60 to do something like that, I would do it myself but I have a machine shop, Im sure you can find someone unless you weld and fabricate then its even cheaper...