I only use two, right now, because my fingers are up to anything more complex. One is a 1-4 tetrachord the other a 1-3.
A 1-4 chord will give you a suspended sound. A 1-3 is just a normal major interval. For the first I just use my index finger and bar the two strings that I want, usually it's the highest two (D+G or A+D *my 4 string is setup like a 5 string) For the 1-3 chord, I use my index and middle fingers. With my right hand, I usually use my thumb and index finger to pull the strings (for a popping sound) or finger them for a fingering sound. I don't have the aim, yet, to strum them. If I try that, sometimes I'll end up doing 3 strings or just the bottom one.
