Here's the standard ST Escort Cosworth borderline spark compensation for ECT. The table is the spark advance/retard for ECT and is based upon rpm and load (I haven't worked out the conversion factor for the tables yet). The multiplier is then used to calculate the amount of advance/retard to be used according to temperature.

SPARK_BDLN_RETARD_ECT_TABLE (rpm vs load)
1.375 4.000 4.750 5.750 2.500 2.500
2.125 4.625 5.500 6.375 3.875 3.875
3.125 5.625 6.375 7.250 8.250 9.500
4.625 6.875 7.625 8.625 9.500 10.875
7.125 10.250 11.125 12.000 13.000 14.000

SPARK_RETARD_FOR_ECT_MULTPLIER (degrees C vs multiplier)
123.33 -0.21
117.78 -0.21
87.78 0.00
-40.00 0.94
-160.00 0.94
-160.00 0.94
-160.00 0.94

The same process is done for ACT.

SPARK_BDLN_RETARD_ACT_TABLE (rpm vs load)
5.750 5.750 10.000 9.000 9.000 5.750
5.750 5.750 10.000 9.000 9.000 5.750
5.750 5.750 10.000 6.250 5.750 5.750
5.750 5.750 10.000 6.250 5.750 5.750
2.500 2.500 10.500 6.250 5.750 5.750

SPARK_RETARD_FOR_ACT_MULTPLIER (degrees C vs multiplier)
123.33 -0.59
121.11 -0.59
37.78 0.00
-40.00 0.27
-160.00 0.27
-160.00 0.27
-160.00 0.27

As you can see the temperature adjustment is very much 'broad brush' and doesn't seem to be needing too much fine control on an ecu that calculates fuelling and spark timing from load vs rpm based maps.

Incidentally there is no idle speed adjustment for ACT. Also, IIRC correctly, the optimum boost setting is around 40 degrees C ACT on the ST.

Edited following a bit more investigation.