UPDATE on page 2:
Update #2 on page 5
Fix update on page 11
The FastenR-T1 is 1mm too deep and will not allow the RC2 QR plate to mount solidly on a tripod; my camera and lens went crashing to the ground tonight because of this. I've returned my RC2 plates to their original mounting d-ring and will be taking my T1s back to BR.
Side by side, you can see the 1mm 'lip' spacer that the T1 is machined into it compared to the original Manfrotto design. T1 on the left, original on the right.
I can't get a side by side comparison with a ruler to show the 1mm difference at the moment as I don't have enough arms or good mount for setting it up. There is a small recess on the underside of the RC2 plate that allows the head of the bolt, on the original to seat into the plate and make room to mate to the tripod body; that spacer on the T1 prevents the head from seating down properly and therefore prevents a solid mounting.
If you've already purchased and received the T1, you can check this for yourself and I urge you to do so before EVER trying this on your tripod.
With the T1 connector on an RC2 qr plate you can rock the gear front to back with the tripod lock in place and remove the entire unit without unlocking the plate. A CRITICAL failure, in my opinion, for BR and I sincerely hope that they respond in an appropriate manner when I get a hold of them.
This took place using a Manfotto 055ProBX + 488RC2 ballhead; RC2 quick release plate, 7D and 100-400L.