\" determine n-widths at different point sizes
\" run this through your troff and examine the output
de nw
ps \\$1
nr n \\w'n'u
ps
Point size: \\$1\tn-width: \\nn
br
.
nw 3
nw 4
nw 5
nw 6
nw 7
nw 8
nw 9
nw 10
nw 11
nw 12
nw 13
nw 14
nw 15
nw 16
nw 17
nw 18
nw 19
nw 20
nw 22
nw 24
nw 26
nw 28
nw 30
nw 32
nw 34
nw 36
nw 38
nw 40
nw 44
nw 48
nw 72