It's great to see that you're interested in propagation
tips and tricks for growing potatoes and sweet potatoes in a tub or garbage can. This is actually a really cool and sustainable idea!
In terms of the width of the plants, it really depends on the size of the container. Generally, you want to give each potato plant enough space to grow and develop, so you should space them out by about 12-18 inches in all directions. As for how many tubers each plant can produce, that can vary as well, but typically you can expect to get anywhere from 5-10 tubers per plant.
I don't have any pictures to share at the moment, but there are plenty of examples online of how to plant potatoes in large containers like old tubs or barrels. Just make sure that the container has adequate drainage and that you're using a good quality potting mix. As for care, you'll want to keep the soil consistently moist but not waterlogged, and you can also add a slow-release fertilizer to help keep the plants healthy.
I hope this helps, and happy planting! Let us know how it goes and if you have any other questions. Take care and adios!