A few years ago, I obtained a used set of Weber 44 IDF's. The mixture needles are somewhat strange. They are similar to the screws in the picture on the far right. I have always used ones like the far left.

I am having trouble getting my idle mixture correct- which should I use (I currently have the right ones installed cause that is what the carb came with- seems wrong to me)?

The center one is the recent replacement I got on my last order from ACE. I called them to ask because the originals looked like the one on the right also. I was told that they have the longer needle and make them easier to adjust. less travel! That is true, but i will be interested in what you find out here also.