Adjusting front face opacity with 'limit selection to visible' enabled

I’ve recently come back to using Blender after 2 years away. There used to be a way to adjust the opacity of the front faces (opposite of back faces) so that, with ‘limit selection to visible’ on, the back faces/edges/verts would appear more/less obscured by the front faces. If I recall correctly, it was a color setting in theme preferences, an alpha value. I’ve tried the alpha value of the Face color setting to no avail. Does anyone know if this is still possible and what value to change? Thanks.