[Groff] dynamic grap ticks

[James K. Lowden]

Is there's a cool way to pass "sh" output to grap's ticks command?  

I'd like to generate my x-axis "ticks" programatically, from the
data I'm bringing in with "copy".  I have a line like this:

ticks bottom out at 6.40000000e+01 "\s-1%.0f", 9.05096680e+01 "%.0f", \
1.28000000e+02 "%.0f", 1.81019336e+02 "%.0f", 2.56000000e+02 "%.0f", \
3.62038672e+02 "%.0f", 5.12000000e+02 "%.0f", 7.24077344e+02 "%.0f", \
1.02400000e+03 "%.0f", 1.44815469e+03 "%.0f", 2.04800000e+03 "%.0f", \
2.89630938e+03 "%.0f", 4.09600000e+03 "%.0f", 5.79261875e+03 "%.0f", \
8.19200000e+03 "%.0f\s+1"

which came from the first column of the data file.  I tried many
variations of 

        ticks sh { awk ... }

without any luck.  (Even less luck because there doesn't seem to be a
way to escape the "$1" I would like to pass to awk.) 

While I'm in the neighborhood, the grap manual says that labels stack,
but mine (version 1.41) doesn't seem to:

$ cat t
.G1
label top "abc", "def"
.G2

$ grap t
grap: syntax error
Error near line 2, file "t"
 context is:
        label top "abc" >>> , <<<  "def"

Many thanks for any assistance.  

--jkl