hi nobleway,
The usual set up in a latin band situation like salsa/timba would be a conga and a tumba and maybe a third drum conga or tumba tuned between the those two.
As for using only a quinto and a tumba, it doesn't make a lot of sense - but that would depend on the tuning more than anything (if you had nothing else then you might get by with it).
Quinto is a pretty small drum and is designed to be pitched high - in Cuba it's usually used for riffing in rhythms like Rumba Guaguanco or Rumba Columbia. It might work in a funk band or some other music situation. Watch out for the Conga Police tho - they might issue you with a citation!

ciao
pavlo