Je pense que le mieux est de faire simple, utilise un espace “classique”. La différence est infime, et ne sera quasiment pas perçue.

Be simple, just use the “normal” space. There’s not a big difference, and this difference will not be noticed.

Spaces between a text and a punctuation mark such as ? ; : and ! in french are only here to make reading easier.

It is customary in french to use thin, non-breaking spaces but it is not required, it is only a typographic convention (as described in the ‘Lexique des règles typographiques en usage à l’Imprimerie nationale’). And even in those conventions, a certain leeway is allowed concerning the width of the space that should be used.

The only thing that should be respected is that those spaces be made non-breaking as it will avoid a punctuation mark to be separated from the last word of the sentence, making it much easier to read.