transistor sizing
you could use any value of W, L and m factor,
and in fact you could use .scale option in hspice to shink you transitor size, for example, you use a PMOS as W=1000u, L=500u, m=100, at the same time you define .option scale=0.01, so you final Pmos size is w=10000*0.0001=100u, L=500*0.01=50u, m=100.
Added after 2 minutes:
sorry for comfuse,
you define w=10000u, l=500u, m=100
and use .option scale=0.01, then
the fize device size is w=10000*0.01=100u,
L=500*0.01=5u,m=100. good luck.