General fuel efficiency questions - 2002 Prius

2002 Prius:

1. Regarding A/C use, is it more economical to not use A/C in hot weather or better to use it due to the battery getting hot otherwise? Can the battery be damaged if A/C is not turned on in hot weather?

2. What is the optimal low/high for pulse and glide? 40-50? 35-45? Something else?

3. I try to keep the glide with no arrows (no regeneration, no electrical engine, no gasoline engine), but it's almost impossible to press the pedal just right. It always shifts to regeneration or electrical engine usage if I hit a bump or terrain changes (like from level ground to an upgrade or downgrade). How do I keep it with no arrows on?

4. What is the best way to pulse? Floor the gas pedal? Slowly push it down and accelerate slowly?

5. What is the B position for? I get that it is engine braking, but when to use it? Does it hurt the transmission if I switch from D to B and backwards at speed?

6. How do I tell if my battery is going bad?

7. Regarding the car's security system, what are my options if I only have a valet key? I can get a COPY of a valet key, but is there any chance the valet key code will be somehow deleted from the computer, rendering the car inoperable? Also, how does the system work? Does it only check the code when I start the car or at random points during the trip? Is there any chance the car will stop while I'm driving it if the connection between the key transponder and computer receiver fails?

8. When does it make sense to drive on battery power (no pulse or glide)?