Hi Shortshifter,
I have already asked 211 Kawa this question and he will only be checking class stuff.
I think I have worked out how to do it.
I have images of Maico's and other makes of bikes that were raced last year and they also never had a cover. Some covers I have seen I don't think would pass this rule, not that there is much detail to it.
If we say that it is to protect fingers from danger than we only have to cover the back section of the cog where a finger could get dragged in. So the cover should start at the centre of the counter shaft and shield back past the end of the cog by say 15mm?
Ji