Really good read! I dealt with various simulations in the past and time is always the most important thing to concider. Interpolation can reduce accuracy and sometimes even completely change the outcome, but looks like you are on track in order to keep these side effects as small as possible. :)
Time steps AND distributed computing are a whole new level of complexity I wasn't really aware of until now. Really nice post, thanks you! :)

PS: I am looking forward to crunch some workunits for you in the future!