The "D" screws are easily replaced to. If you know any guys at a shop anywhere they can probably get you a slotted set from a junk carb I got a set free from a friend that has a Hardley shop. The ones in my carbs I carefully pulled with needlenose pliers when I had the carbs off. Then I carefully cut a slot in them with my Dremel tool and fiber cutting disc.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!