1, My car
Top headlamps are H4's [3 terminal's]
Nearside 2 black, blue/pink, blue/grey and green/grey
Offside 2 black, blue/black, turquoise/green and light/green
Bottom spots are H1's [2 terminal's]
Nearside black, green/grey
Offside black, light green/green.
2, see Tim's answer.
3, see Tim's answer.
4, This is down to the builder, when I built mine I try'd to ensure it had a fall.
The only time I have trouble is when the ground is sloping towards the pump, so you have to think when you go into a garage 'Which Pump Shall I Use'

.
I also put the nozzle in and turn the trigger to the left so it rests on the body [about 8 o'clock, sometime's 9 o'clock].
You could carry a lump of 4 x 2 with you, pull up near the pump, place the timber, move foward onto the timber, fill up

[don't forget to pick it up]
Bob S.