We're greedy so sticking with 200%. lol
Both parts of the equation you're trying to get as close to 100% as possible, but it's 100% of the intended use and that varies widely. On the boat part of the equation, it's not the boat to end all boats, but it's the boat that will do what you need. If it's to cover short distances with fuel economy as the priority then it might be a 7 knot boat. On the other hand, if it's to cross oceans, much different. Or if you want to be able to cross to Nassau in less than a day, very much different.
Same on the home portion. Home isn't to match what your land home might be like. It's situation appropriate. If you're going to live on it, then it might require one set of features. If just weekends, it would be more like perhaps a small lake hideaway. If you rarely spend a night on it, then more like the size of a motel room is adequate. You can come closer than one might think to you individual 100% on both sides simply by being sure you've defined your needs and desires fully.
We each are much different in those respects. But if we're careful in defining our requirements, we can come amazingly close. Now if we start off with an unreasonable combination of boat and home, you're right, a lot of compromise and probably won't fulfill either very well. But that's true on both sides separately as well. If I want to go 80 knots and get at least 2 nmpg, then I just need to start over and redefine my goals.
To me ultimately the key to boat selection is carefully defining your requirements and whether we call it home and boat or cottage or 100/100 or 30/70 or however we look at it, we each need to do that aspect carefully. If we do then the perfect boat for us is out there. But what that is, varies by every individual. And where couples are involved, they have to agree on one set of requirements.