For now, the MC28 manual is the work in progress.
There are plans we are trying to nail down for the other manual. I lost my poor copy of my manual for the MC18/21 so have nothing to work with there. Andy is trying to find time to scan his copy and then I will see if I can find time to work on that with high quality image and content to base it off of.
if anyone has a high quality (read not xerox copy) of the MC18/21 manual and wants to supply me with it, that would help Andy out I am sure.
As for Andy's complaints about the MC28, well let's just say he's biased
I know from side by side personal experience the MC28 is just as capable as an MC21. And not to mention the ease of changing the rear tire, makes a big difference on a Saturday morning when your trying to get things buttoned up to make first practice 
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Charles Gallant