Just about any LiPo when charged at 1C will take approximately 1hr. This is the same for 800mah as it is for 8000mah.
For off-road use you can generally pull it any time it hits the CV mode where the amperage drops way down and the voltage goes up. This is typically 90% or above capacity.
For on-road/oval racing, you will want the pack to be peaked around 8.44v so you need to let it run it's full 100% charge.