I think something also pretty relevant in all of this is the very real possibility of going around from a Cat II app, from a 100ft decision point. As we all know, there is a strong chance of touching down during the course of this maneouvre, and that is even on the basis of having all engines operating. So I have to say that to initiate a missed app from 100ft on one engine in 300m vis is not a scenario that fills me with joy.
My SOP's dictate that above 1000ft agl we complete the memory actions before initiating a missed app, whereas below that point we go-around and then complete the memory actions after. But for us it will always result in a go-around on a Cat II app. This policy makes a lot of sense to me, but of course it does depend on a/c types and their levels of redundancy etc.