I should have mentioned in my other reply.
I didn't just dream up tapering the ends.
I learned it from a guy who used to go by "cordwainer," and now goes by "the cap gun kid ," usually found on the ALR.
He and
@Artificer directed me to a book by Al Stohlman, The Art of Hand Sewing Leather.
Using larger needles, or needles with larger eyes just makes it harder to pull through the hole in the leather, or makes one need a bigger hole. If one drills the holes, the whole can't close around the thread properly, or keep the thread running in the correct direction for a proper looking stitch, as opposed to poking the holes with a diamond shaped awl.