What is a good rooster to hen ratio for roosters to maybe get along?
There is no particular ratio that I know of for that.
The rooster to hen ratios that are often seen, are based on big hatchery flocks that want all the hens laying fertile eggs (so they can hatch the eggs) while having as few roosters as possible (because roosters eat feed and need space to live, but don't lay eggs.)
For many breeds, 1 rooster to 10 hens works well. Some breeds need a few more roosters, some can get by with less. But that is in large flocks (hundreds of chickens).
For small flocks, some people have one rooster with just one or two hens. That often leads to hens being overmated (they get bare backs), but there are some individual roosters that do just fine in a situation like that, and do not overmate the hens. In some other flocks, people have one rooster with 20 or 30 hens, and ALL of the eggs are fertile. Those roosters obviously stay very busy!
For small flocks with multiple roosters, it really comes down to the behavior of the individual roosters. There are some that will get along with each other when there is almost any number of hens (those roosters are fairly rare). There are others that will not get along, no matter how many hens are provided (gamefowl are almost always like that, other breeds not as much.) Of course there are many rooster that are in between those extremes, including most roosters of the breeds that are commonly sold by hatcheries.
Having more hens can help, but having more space will sometimes help more. That is because they can get away from each other and split into several flocks, instead of all the roosters and hens being forced to be together all the time.
Or some people go the other direction, and have a bachelor flock with only roosters and no hens at all. Sometimes those work well (because there are no hens to fight about, the roosters get along fairly well) and sometimes they do not work well (roosters are still chickens, and some individuals just do not get along with each other, no matter what. Some hen-only flocks or mixed flocks have that problem too.)