Tom D. gave me a great gift at the gathering last weekend that I finally had a chance to try out.
He fabricated a piece that goes inside the battery boxes where the knurled fittings go. There is no room up there for a full sized nut. However, he crafted a small piece that will fit in there that is threaded for the knurled fittings.
Here's some photos...knurled fittings in battery box...
These are the pieces he created...I'm not sure what to call them...lock nut plate?