I agree thats good advice about the pre-fill. Most guys over look it.You should also wait 5-10 minutes after pouring the new oil in before you start the engine - this delay allows the oil to fully reach the pan due to the baffles in it.
I also pre-fill the oil filter before installing it.
That is not safe. :eek
Once you lift the rear wheels off the ground, the only thing keeping your car from rolling is the little lip at the end of those ramps. Setting the parking brake or leaving it in gear only locks the rear wheels.
Since it appears you have a sloping driveway, a much safer (and easier) method would be to back into the garage and then drive forward onto the ramps. Placed correctly, the rear wheels will rest on the high spot and the front will be elevated on the ramps. Since the ramps are on the low side of the drive, the net result is that the car ends up level... with all four wheels firmly planted.