Mah... If you want them just like that, I think making a dynamic block (with variable diameter and depth) is fast enough to handle.Yeah, green ones, well, I'm fine with your quick method. . .
Now that you think about it, actually x to indicate the head of the screws is not new to me... but it seems more like a tecnigraph expedient to avoid having to draw bolted connections... but we talk about a method not really "fashion". . .As far as I can see, it is not because the cross (as you call it x) we used it in certain technical offices to indicate to explain the side where the head of the vine or nut came, but it is called prehistory.