Fraction formatt given choice

I would like to give the user a choice of fraction style for a font.
I seem to be stump by the use of the English language once again,
I have attached the formats I would like to create.
There are number of option I could use. Please advise on the best way to achieve this.

I should add I would like the fractions to be random.

I typically include both types of fractions in a text font and only nut fractions in display fonts. I personally prefer nut fractions but realize that it may not be what a user expects.

Those two kinds of fractions have different OT features:

  • diagonal fractions go in the frac feature
  • nut fractions into the afrc feature

I suggest doing only precomposed fractions in afrc. There has been a partial solution posted on TypeDrawers, but it is pretty complex and has its limits.