Natural marked with a sharp symbol (mensural notation)

[Niols]

Hello,

I stumbled upon a score in G minor where a E natural would be marked as 
a E note preceded by a sharp symbol. What would be a “clean” way to 
achieve that?

I have thought of redefining the natural symbol by the sharp one, but:

  1. I don't know how to do this.

  2. This would not work in an other key signature with sharps where, I
     assume, the natural would be marked with flat symbols.

I actually found something about this in the documentation here:


http://lilypond.org/doc/v2.19/Documentation/notation/typesetting-mensural-music#mensural-accidentals-and-key-signatures

It does say that the natural symbol does not exist really and that the 
sharp or flat is used more often. However, I could not see a clean way 
to say that I indeed wanted that.

As a bonus question, what if I wanted the sharp from the mensural 
accidentals to be bigger in my score (I find the default one really tiny).

Thank you so much in advance,
— Niols