Note that if you sum 1+2+3+4+5+6+7+8+9+10, that's already 55. How many time units do you have per 48 seconds ? (do you have a base tempo at all ?)
And then what do you want the distribution to be like ? Is there any maximum duration of a chord, minimum duration of a chord, etc ?
It's funny that you said that. I slept over this problem and yes, I want the chords to have a minimun and maximun duration. They don't need to bee all of different durations, the important is this section of the piece to sound like random/chaotic durations, and as we know random numbers (or durations?) sometimes don't look random. I will even make this again for the attacks of individual notes of the chords so the section will have a truly chaotic feeling. And by the way the tempo of this section is quarter = 60 so it's very easy to do this. (thank you Mathieu for making me think about it more deeply)
Thank you guys for the other answers. This really helps.
Caio Barros