What about this method (actually only works for uneven number of chords, so maybe drop one, or increase to 11 and drop one later( randomly? ))

Just pick a random float between 0 and 48, we'll call that X1
Then pick a random float between 0 and X1 , and between X1 and 48, call those Y1 and Y2
Then do it another 8 times and you have 11 random positions within your range of 0 till 48 ;)

Not sure if it will actually work out, but I just had this brainfart after seeing this thread go on so long :)

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