You don't really need any tools
Astrology is (contrary to astronomy) much more a cultural aspect than a scientific one. You could spend a lot of time in finding out how the trajectories work, but the important part of astrology is more along the lines of what the interpretations of the stars would be.
To say "planet A is reaching the house of starsign B, so that must mean a war is coming" you don't really need to know how long these planets should take to travel the skies. You only need to know which planets there are, which starsigns there are, and what the interpretations would be.
you would need to know the order of your starsigns.
It's true that modern western astrology gives a meaning to latitudes, altitudes and all sorts of other 'tudes, but this is a rare concept. Some cultures look at the brightness of certain stars, others don't even look at stars that are always there but only keep an eye out for shooting stars. you can make your Astrology however you want, man. Don't force yourself to make it look like what we already know of.