BondAR

Hi everyone, I'm converting my 69 cutlass from auto to manual. It appears that both fine and coarse thread screws are offered to hold down the z bar bracket to the frame. Which one should be used?
I also noticed that there are 2 different z bars, each with their own upper rods. One z bar has an integral bushing and a rod that has a longer shank to accommodate the bushing, whereas the other has no bushing and a rod with a shorter shank. Is one preferred over the other?
The engine is a 455 if that matters. Thanks.