Based on what I used in the past, before the NiMh / LiPo / LiFe era!!!
1. Charge rate= 1.5 amp (based on 1C) ?
When charging at a low rate, the battery become lazy.
At least 2C, thus in your case with 1500 mAh bat, charge it with 3 Amp.
NiCd has memory effect. That means, before charging it, you want to discharge it completely first (e.g. use your charger or use a car lightbulb and connect it untill the light is off).
2. Dischrage rate?
As much as possible, depending on the capacity of your discharger. For races, they are discharging the batteries even up to 35 Amp, using several car light bulbs in parallel!
E.g. Deans Discharger
3. Capacity cutoff = 1200mAh ?
To prevent misdetection of the charger when the battery is full, set it according to the capacity of your battery, thus 1500 mAh
4. Delta peak sensitivity = _mv/cell?
With 6 cells, about 20 mV
5. Temp cutoff?
Approx 45-50 C. Not mandatory to be used. Also not accurate because affected by surrounding temperature.