Talking about 5 gallon buckets is probably confusing people so don't do that.
Ratios have been talked about dozens and dozens if not hundreds of times here on PWI throughout the years, just do a search and you will find all kinds of examples.
It does not matter what the ratio is but when you start talking about container sizes to people that are not that familiar with ratios as it is, you might confuse them more, keep it simple and don't talk about 5 gallon buckets or bucket mix or anything else like that, that is not important at all, it just confuses people because you don't know what they are mixing or the quantity, only they will know when they are mixing their chemicals.
Ex. A 5:1 ratio or 1:5 ratio is most of the time meaning that the 1 part is the chemical and the larger number is the water typically, things change but most chemical containers will tell you what they mean on the label, info page, instructions, etc.... so you would have 5 parts of water in the container and add in the 1 part of chemical (like with most chemical mixing, add the chemical to the water, not the other way around, that is why you already have the 5 parts water in the container waiting for the chemical).
Depending on what size amounts you are using, quarts, gallons, buckets, drums, etc....... that will tell you what size container to use for mixing, always have a much larger container than what you need in case you have to stir or mix, none will splash out and make a mess.
Let's keep this simple for those that are learning, confused or have not grasped the concept yet or got it all down yet.
Like always, if you have questions just ask if you cannot find it using the search button.
Hopefully this helps.