I'm still finding this function awkward. Using nimbus-12 on an H120, the vkeyboard takes up a huge amount of space and spills onto a second screen because the font is rendered as fixed width, rather than proportional, thus making it display much larger than it needs to be.
It's layout could be adjusted to fit nicely if it displayed as proportional.
This is a shame, because the principle is excellent.
If somebody could point in the right direction (which function) to start with, I would take a look at the code to see how easy it would be to patch...