10.5 min for maybe inversion tanks, so you may reduce for rotary about 15%, sorry i am not expert and i can't help but i post something to be active than nothing, you can give it a try and see how you will end with, if you are looking for a certain look and accurate then better find another answers, here just for starting point testing.

http://www.digitaltruth.com/devchart...tol&mdc=Search