It may be possible to allow for users to add overflow layers, which would be dynamically drawn if the gauge exceeds maximum values. I'll think on it some more, and see if I can come up with anything I think would fit. As always, though, open to suggestions.
As for clickable labels, Vyzor doesn't wrap the Mudlet API in the same way Geyser does. Instead of calling an OO version of setLabelClickCallback() on a Geyser object, you can just use the bare Mudlet function. The name you pass in the Frame constructor is the name of the label.