3 weeks is about the limit of how far in you want to be.
Low branches have LOW concentrations of auxins so don't expect lightning fast results.
Dip-n-grow seems to be the best cloning hormone for difficult cloning situations (it has a fungicide, which buys some time).
Scrape the bark off the side of the cutting for the first cm or so, because it will allow the hormone ot be absorbed better and the roots to break through easier.