#+TBLFM: $s=uconvert($W*$l/$Z,kg / cm^2)::$cs=uconvert($s_lim/$s, )

where uconvert is defined as:

(defmath uconvert (v u)
  "Convert value V to compatible unit U."
  (math-convert-units v u))

But no luck, "cs" result is an ERROR. Is it feasible to get a value for "cs" with no units?

Ok, it is enough to add any unit to uconvert, for example: $cs=uconvert($s_lim/$s,m). That simplifies units in adimensional parameters.

Best regards ;D