Matched sets are mainly for discussing a twin inboard engine, however it can apply to your spare as well.
Our goal is to ensure that the performance is the similar, even if the manufacture is different, afterall, the saltwater isn't checking to see if the propeller is from a name brand. What should matter is the way that the propellers are tuned and straighten so that they meet minimal ISO Class I or Class S tolerances and each have appropriate pitch and balancing.
We've been asked many time, "can I just buy a prop that looks similar and put it on", well the answer may not surprise, yes if you want to create an unstable condition for the boat and potentially burn more fuel and impact performance, our answer is to go back to the original specs of the boat and what it called for so that you can have a better boating experience. Or try our sizing form and see what other options are available.