In your .cdsinit add the following "cdsenv" type settings:

envSetVal("spectre.envOpts" "simExecName"
        'string "/path_to_spectreLimit")
envSetVal("spectre.envOpts" "controlMode" 'string "batch")

The first variable sets a different executable for spectre - this
should point to the new "spectreLimit" script shown below, the second
variable will restart spectre for each individual run - this is
required so that you can limit the cputime for each individual
simulation.

spectreLimit :

#!/bin/csh -f
# A script to call spectre with a time limit

limit cputime 100
spectre $*

In the above script the limit is set as 100 seconds, you should
replace this with a value that you have decided is a reasonable limit
to allow most simulations to run to completion, but stop those that
get stuck.