Hi all,
I thought I'd share this find. These headlight adjuster nuts for sale on Ebay fit and work perfectly for Henry Js:
https://www.ebay.com/itm/145951909640I took a gamble and ordered 4 of them since they looked very similar to the Henry J adjuster nuts, and two of mine rusted and broke. They are a slightly different design, but they fit and work perfectly. The design difference actually adds some strength to them. Anyway, I just tough I'd share.