Rule of thumb with yeast:
"Instant" "Rapid" and generally speaking all packaged dry yeasts are so close that it doesn't make a lot of difference which you use.
"Active" dry yeast is somewhat milder than their faster counterparts so you should probably use about 1 1/2 times the amount of ADY compared to the speedsters.
Cake yeast is not comparable in any case; kinda in a class of its own.
I came across that rule of thumb somewhere, and I try to approximate it since I have only rapid rise on hand most of the time. Activated and the "speedsters" are not the same thing (although the speedsters pretty much are the same), but there are so many other variables involved such as rise temperature, the age of the yeast and the like, so don't get out your scale and calculator. If the recipe calls for a tsp of active yeast just make that a scant tsp of rapid rise.