I use a rMBP (3.57 Lbs.) with a thunderbolt display. I am looking for a stand to work in clamshell mode. I'm considering using this twelve south shelf to hold my rMBP out of sight behind my TBD. The twelve south site lists the maximum weight as 3.5 Lbs but the rMBP 13 is listed as weighing 3.57 Lbs. Anyone out there using the BackPack 2 with the rMBP 13? Is the shelf sturdy enough even though slightly overloaded? Any other alternatives to hold the rMBP 13 behind the TBD in clamshell mode? The BookArc is a possibility but I would prefer something hanging on the back of the TBD.