I've been fiddling w/ this issue for a while now and have tried many different containers. Electrolyte capsules are very important for me and I HATE stopping to take them. My current favorite for easy one-handed operation on the bike is an empty tic-tac box. Reinforce the lid hinge w/ a few small pieces of scotch tape. It holds about 10-12 capsules. It's super easy to flip open the lid and shake one into your mouth. It's fairly waterproof (although many hours in a sweaty jersey pocket is pushing it). Try it and let me know what you think.
BTW great job in this event!! I agree, the team relay concept sounds like a lot of fun.
If you're not already using them, you might want to consider S-caps. They are significantly more concentrated than most electro-tablets. One an hour is plenty and you're probably stopping at least that often for other things.
My problem with all such tablets is that they tend to break (obviously, they get jostled a lot more running than biking). I put mine in the same bag as my TP supply, which seems to keep them in tact pretty well. Of course, if I have to stop and actually use the TP, I need to be careful not to dump them all out.