There has never been an official ruling on this, as far as I can find, so is it legal to use custom stickers in a different font on number plates? This is assuming, of course, that the new font is readable for the audience and referees. No rules seem to clarify if this is legal or not. This has been allowed previously at Worlds, such as by 365X (and I have to figure that they would have been called on it, if it was an issue).
Additionally, do these letters have to be precisely the same size as the standard ones, or is some leeway allowed? And do stickers used have to be transparent?