jrock,
I dive a Zeagle Brigade(Ranger with smaller bladder) up here in Dutch Harbor, Alaska, and usually have it loaded with 28 pounds of lead (10 in each side of the ripcord pouches, 4 in each side on the tank weights), and have no problems with weight shifting.
I dive the same BC in tropical water (10 pounds lead), also no problem with weight shift.
You should put your weights inside of Zeagle's yellow weight thinggies, which help fill up the extra space inside, and are just rigid enough to keep the weights from shifting around. I use the same thinggies when diving wet or dry, no problem with putting less than their capacity inside of them. If I'm lazy and just jumping in the pool, I've put my weights in the weight pockets without the thinggies, and its usually not a problem, although there is a little bit of a noticeable shift. Without the yellow weight thinggies, smaller weights (1-2lbs) might be able to work their way out of the bottom of the pocket... maybe.
IMHO, the Ripcord system is one of the best designed systems for releasable integrated weights.
Let me know if you have any questions, or want to see some pictures to illustrate anything!
-B