I will go with this on my next set up, I run BBs now and you have no way to add more with out busting the bead.
Bruiser posted this somewhere:
To add the fluid to your tires, While the tire in on the rim and mounted to the Jeep, remove the valve center of the valve steam to allow it to go flat, take piece of rubber hose just larger than the valve steam so it will slip over the top of the valve steam snuggly. Fill a bottle or container with the anti freeze and water measured to the amount your wanting to add, insert the hose to the bottom of the fluid, sit it beside the tire and jack the tire off the ground, when the tire expands or debulges it will suck the fluid into the tire. easy as that.