The acetate ester has a 3 day half life where the prop ester has a 4 1/2 day half life I'll list a few and give you a link, I'll also say that the reason you don't see test ace so much is that it's more volatile and harder to work with, it crashes a lot and it's tougher to make a pip free product. At this point I think most every source has a pip free prop when not to long ago I remember that being a huge selling point, people would even mark their prop as pip free prop on their lists and websites.
test ace- 3 days
test prop- 4 1/2 days
test e- 10/ 1/2 days
test c- 12 days
Test suspension or tne- 1 day
Here is an awesome write up that will help you calculate drop time before your pct, it's helpful thru your cycle if you want to change things as well.
http://www.british-bodybuilding.co.uk/Half-Life.shtml