The idea of the bearing buddy is to stop the Ingres of water and loss off grease. Keeping your bearings serviceable for much longer under harsh working environment .
The correct use is to lube up your bearing as normal, pump grease in to the nipple on the buddy until you see the piston ( plate the nipple is mounted too) start to move outwards. You want the piston to be approximately halfway (a bit more on newer buddies) along its travel. Under this situation if the hub heats up the grease expands and nothing escapes, if the hub rapidly cools ( aka water dunking) the grease contracts dragging the piston in not water.
You should not have to keep pumping grease into them. The use of marine seals is required, but IMO they are a better seal anyway, regardless of using bearing buddies. Quality marine grease is important as well. Always carry a spare as they get nicked, knocked off, fall off etc.
I don't think they would be necessary on a CT unless you planed on making a zillion salt water water crossing other wise you are just giving yourself a headache on something to keep another eye on.
Even with buddies, I find the best advice even given to me about dunking any trailer or vechile in water was to wait and let everything cool down before it's dunking.
The newer cheaper bearing buddies are not as good as the original more expensive brand. The pistons are pressed and do not work as well. Best brand I have found recently Other than the genuine are "Trojan" from
Repco.