Just an update if anyone is interested:
I used the same size stitch holes (I'd already had two other bracelets pierced), and used the same size thread (277).
Knot on the needle was coming loose: I pierced the thread with the needle and knotted it, and I had a much easier time keeping a tight knot on the needle during stitching.
Stitches were loose: I waxed the bonded nylon thread (tied it to a shelf on one end and held it taught with my left hand and ran a wax stick over the thread length about a half-dozen to a dozen times back and forth, top and bottom), and I pulled each stitch much tighter than before. The stitching, even after bending, feels firm and set.
Thank you for the help!
(Oh, I realized the other night I had accidentally created a second account some years ago! Klover = Hydra.) 😅