Being new to wall brackets I would appreciate a little guidance. I would like to wall mount a 15kg Sony 46” and will later attach a soundbar to a mount that will hang from the TV mount. The TV mount must have the facility to pull out and rotate. I have found one on 123 brackets the Cantilever pro series 2. This has a large wall plate. I have dry lined walls and my thought was to find the battens and fix some hard wood between them and fix the bracket to this. I would drop the HDMI and power lead between the brick and plasterboard and poke it out from the bottom where it is hidden from view by the cabinet. Are there any obvious lessons learned from experience that I should be aware of?