I'm not sure if this helps... but I use drip jugs in my gardens. Not quite ollas since I don't really bury them. But I fill them off my rainbarrel and let them soak in. I use 1 gallon and 3 gallon jugs for this, depending on the bed and plants.

You don't say how it wasn't working, but gravity-feed drip systems require special low-pressure drip emitters (1-2 PSI), depending on the height of the tank. In fact, the emitters have to be matched to the pipe length. Long pipes mean lower pressure and larger emitters. Do you have those? A line-feed drip emitter (20 PSI) won't work when doing gravity-feed. Nothing will come out.

I bought a drip irrigation kit from Amazon and it just wouldn't get to all of the plants consistently. Some plants would get a ton of water and some would get none. I don't have the specific emitters you are asking about and I'm beginning to have doubts as to whether I can get this to work. Watering with the hose isn't that big of a deal, I just thought this would be pretty cool.

Well, if the Amazon drip irrigation kit was specifically for line feed (as in, home plumbing), it won't work with gravity feed. If it was specifically for gravity feed from a tank, it should, and you should get in touch with the manufacturer about problems you're having with it when using a tank.