Joaquin Pozo, a great conga player who plays 4 congas, uses a tumba, 2 congas and a quinto. He came up as a comparsa quinto player in La Habana. Very effective use of the quinto in 4 drum rumba-based rhythms in his Latin Jazz and timba/mozambique/salsa music.
Descarga Cubana, he is playing a mean marcha on 3 and 4 congas, playing quinto riffs on top at the same time, no overdubs.
https://www.youtube.com/watch?v=hohYbLXuPXACheck out his Rumba Para Dos, rumba- and conga-based marchas on 3 drums, quintoing on the 4th, sometimes singing the melody with the drums.
https://www.youtube.com/watch?v=TGGQ3k9nw30Envidia Por Dentro is a slower salsa-like tune carrying the marcha on the quinto. Check out his marcha from 3:55 to 4:12, essentially on 3 drums. Nice 4 drum marcha variations in the last few seconds of the song.
https://www.youtube.com/watch?v=OdzK-RDCahcEven though the quinto can be well integrated into a 3 or 4 drum set of congas, if you want to play with a band, it is probably best to start out with 2 congas and a tumba or a conga and 2 tumbas as others have recommended until you are able to play quinto while holding the marcha or rumba base really solid on 2 or 3 other drums. Also, a conga is usually lighter than a tumba, so 2 congas might be better for you if you are based in NYC. If you want to learn the style of playing quinto while you hold time on 2 or 3 other drums, you would want to get a quinto to learn on and learn to play quinto at rumbas. Depends what music moves you the most and what playing style you want to develop.