Macro with the G7X : magnification
The original post is about max magnification but this is not the whole story. Indeed, a large magnification is sweet, but it is much better if it can be achieved from a reasonable shooting distance.
And while close up lenses permit to decrease the minimal focusing distance, they also decrease a lot the maximal focusing distance.
+10 diopters @100mm
To get an real world idea of the working distances...
+4 diopters @100mm
With the +4 diopter filter, you loose magnification, but you gain a lot of versatility wrt magnification, while retaining comparable working distances.
Without a close-up filter
Let me recall magnifications without a close-up lens, @100mm...
By reducing the FL, it is possible to increase magnification
...but you need te be much closer.
+4 diopters @50mm
with the following working distances
+10 diopters @50mm
With the +10 filter, wrt to the first sample of this post, by reducing the FL, you regain a fair amount of versatility while keeping a fair amount of magnification (actually better than @100mm with the +4 filter). But you need to get quite close to your subject.
All in all, I think that the +4 filter is appropriate to carry in a pocket everywhere, for quick and casual close-up shots. The +10 will be better suited when you'll have a little more time and specifically intend to shoot close-up.
Sorry for beeing long. I don't expect answers, actually. The point is that this is the kind of information that I've been looking for, but that I couldn't find by Googling. So I hope that it can help future Google searchers. It's not a post meant for "debate".
PS : a Playmobil toy is approximately 7.5 cm (3 inches).