I have been considering using this method myself but have had concerns that the quick release clamp might open while carrying it. Has this been a concern for you?
I would absolutely NOT use a lever release clamp for this. The screw clamps have a fair bit of intrinsic tension and it takes an intentional effort to open one. Also, positioning helps - for a body plate/L-bracket, orient the clamp so the screw knob is under the lens, for a lens plate/foot, orient the clamp so the screw knob is away from your body.
When I started using this setup, the RRS clamp wasn't a viable option - their B2-FAB was their offering, and it has little nubs on the bottom that prevent the BR lug from sitting properly. Usually, RRS advice is excellent - in this case, their advice was to 'mash the rubber washer down onto the nubs, or just file the nubs off'. I bought the Kirk clamp, after telling them that their advice was rather lame. Apparently, I wasn't the only one who thought so, more recently RRS came out with a flat-bottom version of the B2-FAB specifically for a BR-type setup. Even so, when I needed a second clamp for a second BR strap, I went with the Kirk clamp - extra jaw length really doesn't add any security, and I prefer the 1" Kirk clamp to the 1.5" RRS clamp.