I followed the instructions on the above mentioned post for wrapping the bricks in pairs and took Asha Wagner’s advice for securing the bricks in a GORUCK pack using Sea to Summit ¾” straps to secure them on the ruck’s internal PALS webbing. To the right are two pairs of bricks (4 total) in a GR Echo.
I’m pretty light, just under 150 most days, so 4 bricks is the prescription. A yoga block is the perfect thing to fill the extra space—dense but soft and about the size of two bricks. One note is that you can indeed fit 6 bricks into a GR Echo, with just a bit of room to spare. The third package of bricks takes the place of the yoga block, with a bit of space on either side. Unfortunately, there isn’t nearly enough space for a hydration bladder along with them. If you’re taking 6 bricks to the Challenge, get a GR1 or Radio Ruck.