I think the biggest problem was making the damn screws. I seemed to lose the brass inserts and then accidentally marred the long thingy.
The other problem was and still is the loose fit of the screws in the factory configuration.
Unlike the majority of folks doing it, I wanted to be able to align the bore axially. The best way to do that is to center the bore at the front spider and then move the long thingy in the rear spider until the long thingy is axially aligned. It's not really that simple, but that's the principle. To make sure it doesn't move does take some pressure. If I remember correctly, I accidentally marred a glass peened thingy once and then switched to a copper sleeve to stop that from happening. The sleeve worked so well that I never went back.
Same applies at the front. Some guys use aluminium L-shims to allow the thingy to bend axially. I found heavy gauge copper wire worked better. And a thin sleeve of copper pipe worked better yet.
I still have an assortment of brass tipped screws and I still use them, but my assortment of copper sleeves gets used much more often.
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