I bought a Ferrule crimper set from someline on Amazon, which unfortunately was only padded with a few pieces of foam and wobbled around.
so I made an insert. The insert is a snug fit.

Amazon link:
SOMELINE® Ferrule Crimping Tool Kit,Self-Adjusting Pliers for wire ferrules AWG 24-8,With 9 Sizes Insulated Wire Ferrules Terminals,Square Crimp Connector Assortment Kit (GX9-4)