Hi Chris-
Nice! This looks like a couple of good resources for people who are speccing out their drive systems. Your ~0.9 factor for what the actual speed of the CIM is a decent estimate for the general case, I think.
I think one of the great parts of this is your careful attention to what units are being used at each step of the process.
I agree with John's thought on making it as clear and understandeable as possible. You can never stop making it easier to use.
Not that these ideas would make it easier to use (probably the opposite

) but how about at the important parts of the calculation having a link which describes the calculation that is going on behind the scenes? Or how about a couple of plots showing the results that got generated (top speed versus gear ratio, for example). How about a pushing force calc?
Keep up the great work,
Ken