Print strings without sharing characters
CJam, 0.24075

Programs

BA1]100cf|
"two"
{hree}`W&lt;7a.-
N)92+_9+_6+_2~+
S(84^I^U$F^X$G^Y$(
's'i'x


Thanks to @user23013 for his suggestion to use ' for six.

Output, length, score, used characters

one    10  0.03162          01       AB         ]    c f         |  
two     5  0.08944  "                                     o  tw     
three  13  0.02133        -.     7  &lt;        W     `a e h  r    { } 
four   15  0.01721      )+    2 6  9      N       _                ~
five   18  0.01309   $ (       4  8    FGI SU XY ^                  
six     6  0.06804    '                                  i  s  x


Verify the results yourself in the CJam interpreter.