I've tried doing that as well, in some cases, but there's not much info available.
Osa's are generally in units of 6, and Komars in three units of 6 (18 total), due to the latter only have two missiles each. Of course, that's the fully functional org., so they may have fewer actually serviceable – generally anywhere from 50% – 75% ready, with 60% – 67& serviceable being the norm, from what I've read for many military/naval organizations.
To take on larger vessels, a lot of the smaller ones are supposed to use swarm tactics, and to launch numerous missiles at once to try to overwhelm the target's defensive weapons and systems.
Many nations seem to at least have their boats operate in pairs, trios, or quads (two pairs), depending upon the situation. Some, with 5 or 6, or more, if they're available.
Probably your best bet is to look at the numbers and types of vessels actually used during the various conflicts and time periods you're interested in, and extrapolate from that.
Hard for people to criticize you on what you decide (other than perhaps 100% serviceability for a nation), since there's little real data out there, at least that is open source.