i've taken both the SAT and ACT essay and have scored 10+ on both. i think you can write an SAT style essay for the ACT.. if you can. i found it tougher to use specific examples for the ACT prompt because the prompt for the ACT is usually a direct question. for June it was something like this.. "Do you think companies should be able to market products that are harmful to people?" the question is so general, yet specific at the same time.
if you can think of good examples in history and literture then by all means use them, but persoanlly i could not. i had to use reasoning and rhetoric to argue my stance. overall though i think you can write an SAT style essay for the ACT. the extra 5 minutes also helps a lot

good luck