Font size is bidi module

I have been using bidi module for some Urdu text and overall it works really well. However I have hit one small niggle.

The documentation for +bidi-arabic-font says

WARNING: if you specify a size for this font it will hard-lock any usage of this
font to that size. It's rarely a good idea to do so!

and that makes sense and setting a size indeed makes C-+ etc stop working.

However accepting the default font size and then using C-+ and C-- to get to a good size for the font then break the spacing between words and size for the punctuation. This is because +bidi-arabic-face is set using +bidi-arabic-font but at a fixed size so what the documentation of +bidi-arabic-font is warning against happens and after using C-+ and C-- the text looks either too cramped or too spread out?

It seems to be that both +bidi-arabic-font should be a font family name and not a font spec and +bidi-arabic-face should specify the :family and not the :font.