My advice is to create specialized Assistants.
A vector store with 200 files in it is massive. As long as those files had descriptive names, you could create a workaround for not having custom meta data yet; but this doesn’t help finding information within those files if they are also long.
Ultimately, if you have everything in one Vector Store, then a model would have to potentially search all of those files which GREATLY balloons inbound tokens, thus making an accurate answer less likely.
But this all depends on your purpose, and what you want to draw out of the vector store.
If you’re asking questions about how one project is related to another, then one Store is probably what you need. But if you’re interested in accurate information about each individual project then create a specialized Assistant for each project. Depending on your needs, this specialized assistant could be built in 4o mini for routine search and retrieval.
Then, once retrieved, give the collected data from the many mini Assistants to one smart Assistant for analysis and insight.