Yep, that's how it works. When you make the rap on the second biner, use the part of the rope that's between the second biner and the Blake's. You may have to feed a bit of slack to have enough to clip into the biner then bring it under and clip in again.
I use it solely for descending, so I've never used like that, but I think you could, just experiment with it.
My advice would be to test your assumptions low and slow, that way you won't end up sore & grumpy Jeff. lol
The only problem(a small one) I've had with it is the fact that it likes to eat your glove if you let the sleeve of the glove get in there. I use those mechanic's type gloves with the Velcro strap, the sleeve on them is pretty short and gets in the rig sometimes, but with the right gloves you probably won't have that problem.
