The Chinese natural stones are a very good option, but they require some experience. If you don't have any, I would suggest something like a naniwa 12k (the naniwa super stones are quite cheap compared to the other synthetics) , sigma select 13k (a very good choice, but costs), shapton 10 or 12 or 15k etc etc. For a finishing stone, you don't really need a slurry stone, just plain water. But to answer your question, any high grit, hard stone will do the job, be that a coticule, a C12k or even a small piece of translucent arkansas. Many people prefer the norton 4k-8k combo. There are also the barber hones. Personally, the Chinese 12k stone is one of my favorites. Do you have a leather strop with any fine abrasive pastes or sprays or something like that? For a razor that doesn't quite feel as fine as it was when you first tried it, it might not need honing right now. A little stropping might be enough.