That 10 to 1 you often see on here comes from hatcheries where they want high fertility. With the way they keep them, in the pen breeding system, that ratio is what is used to assure practically every egg is fertilized. It is not about behaviors, it is about fertility. And, like every other rule of thumb on here, it can be misleading. The hatcheries keep track of fertility within individual flocks and adjust the ratios as required. Some of their flocks need a ratio of 7 to 1 while others have perfect fertility at 15 to 1. That 10 to 1 is often quoted on here for something it has nothing to do with (like behaviors) and is only ballpark for fertility in our flocks.
but with 7 hens, the 2 boys should be fine, right?
I don't think you are concerned with fertility, I think you are concerned with behaviors. You should have different concerns.
One, with multiple males, is will they be able to coexist without one killing the other? They will establish which one is dominant. That may mean a fight to the death, it may mean that they work together to take care of the flock. Individual personality has a lot to do with which you see. Some can work together, some can't. Space can have an impact. A common model for roosters to be able to coexist is where each one claims a certain territory and attracts what hens he can. The males stay away from each other. That's the way they usually do it in the wild. Very few of us have that kind of room. But sometimes they hang together during the day and get along. I've seen both happen.
Another concern is will your hens become barebacked. Will they be mated so often that the roosters tear the feathers off of certain spots and expose bare skin. The males stand on the hen's back while mating. They have pretty sharp claws on their feet. If the mating technique is bad (as it can be especially for juveniles) the claws may cut the exposed skin. Some females have brittle feathers, feathers that easily break off. Even if the male's technique isn't that bad she can still get bare spots which can be cut. The more they are mated the more likely they are to get bare backs.
Then you have over-mating. Especially when they are juveniles, the boys' hormones may be running wild. Those hormones drive them to mate a lot. The girls don't have those hormones and are not mature enough to accept the boys' mating urges. So the boys can be fairly violent forcing the girls to mate. The girls, naturally, get extremely nervous and try to avoid the boys. There are plenty of stories on here where pullets spend all day on the roosts trying to avoid the boys to the extent they have problems eating and drinking enough.
These are generally worse with juveniles. Once the boys and girls mature into adults these problems often go away, though the males can fight at any time. Sometimes they don't go away. They each have their own personality so you never know what any individual will do. You do not get guarantees with behaviors of any living animals.
My suggestion is to define your goals. Why do you want any males? Then keep as few males as you can and still meet your goals. It is not that you are guaranteed problems with more males, but the more males you keep the more likely you are to have problems, some serious. And pay attention. If what you are trying doesn't work out be ready to change.
Good luck!
