Ideal tyre width for rim width 8″ and 8.5″?

Halo, next year it should be new 19″ rims for my BMW. What I definitely want to avoid is that the rim “looks out” over the tire. This is not only optically unsightly, but also a real danger for the rim (bord stones). Speak from experience. I suspect that one can still take good for the 8″ 225, but for the 8.5″ it should certainly take 235. Unfortunately there are hardly 19″ the 8″ wide. 235 tyres are actually too wide for me. I also want to What do you think? Greeting Michael