Efficient filing and searching in Penultimate

[Alec Eiffel 0]

I'm totally new to penultimate and going paperless and struggling to get my head around efficient filing. 

If I have upwards of 350 clients around the world how can I file my notes for each client and then quickly search for them within penultimate?

A notebook for each client seems like overkill, but the search functionality within handwriting seems to struggle on company names that aren't recognisable words.  

For instance one of my clients is called SND.  Despite writing it very clearly at the top of the page Penultimate/Evernote can't find it.

Any help/tips/advice gratefully received.