I would tend to avoid glue if I can and use methods that are removable and cause no damage in case there is ever a need to take it apart.
I will usually use strips of leather wrapped on, using thin stuff if I can makes it neater.
Trim the shape with a very sharp knife, and use a slim bar of steel under it to make sure I don't cut through.
Then at the outer edges of it through the braid under, attach either dental floss or artificial sinew, and wrap it (flat) as if I was doing a button, ie 20-30 degrees apart past the last one on each pass. every now and again going through the braid again. The artificial sinew spreads out to about 5mm width so it works far better than dental floss which only spreads about 2mm-3mm
I used to use tape to smooth the finished look but don't much find the need any more, if the floss is good and tight and even, it shapes it nicely enough. And helps to provide a better grip for the next knot.
If I am out of material, I will make more knots using what ever I am braiding with, usually a Spanish ring, if I need a rein type knot, or if it's for the end of a whip, a Spanish ring followed by a turks head followed by what ever know I am using.