You only use it if you can't coax the bun to eat on their own. If you can get them to eat at all you really don't want to force feed them because of the risk of asperation (going into the lungs). I tend to make it with cold chamomile tea and fruit flavored baby food to make it taste better. Canned pumpkin is also good to have on hand.
I personally give my buns canned pumpkin in a dish about once a month just so they are used to eating it. If you are trying to get something into them that they never have it can be more of a fight. Plus, sometimes they can lap up the soft food when they don't have the energy (or having head tilt) to chew hard pellets. In that case I mix some of the CC or pellet dust with the pumpkin and let them lap it up on their own. I get pellets in large 50 pound bags and by the end there's always dust that settles. I just dump it into a jar to keep on hand, it's basically unflavored CC.
The amount depends on how big your bun is. In general you would feed them as much as they will take 3-4 times a day. When they start to spit it out they are done. Sometimes you have to coax them to chew. I will cheer and coo with every bite. You would also want to make sure they are drinking enough if they are that sick. Pedialyte is generally well accepted and also good to have on hand. Apple juice diluted can also work in a pinch, but it is higher in sugar. You can also wet down their greens to get more fluid into them.
I don't think you could have done anything for Molly, but it is good that you are getting prepared. I would also advise having first aid supplies (cotton gause, plain neosporin, betadine, tweezers, paper tape, vet wrap, udder cream, simethacone baby drops, metacam, sterile saline) and fever supplies (themometer, ky jelly, rubbing alcohol, possibly sub q fluid kit from your vet- obviously they would need to know when you have fever issues, but sometimes this can get them through the night until your normal vet opens). It's much easier to get supplies to have on hand when you don't need them than to be in a panic at the pharmacy. I have built up my kit over time and added on as I found I needed things. I feel much better prepared for crazy bunny emergencies that always seem to happen after the vet is gone for the day.
