(not including time spent on flushing, draining and filling coolant)
Speaking of which... the owners manual says that I need aboot 13L of coolant... But I could barely get in 6L. I've tried 'burping' the system, but I didn't seem to do much.
That's system capacity, how did you drain it? You're not going to drain all the coolant in block/heater core/etc without a pump or getting creative. If you just popped off a rad hose or replaced what leaked when you pulled the pump 6L is probably about right.