Something I've considered, though am weary of, is the fact that the adjuster resembles a set screw. I have found a source for various length set screws (allowing for a bit more length to incorporate jam nuts) with a variety of hardness, and with what they are terming an "oval tip". My concerns regard both hardness and shape of the "oval tip", as it is risky putting such unknowns in an engine. Best not to mess with unknown wear characteristics to save a few bucks--OK, more than just "a few" bucks, but still not worth the risk.
Trend Products also seems to manufacture adjusters, but I've yet to locate a source or pricing. Looks like they are out of Warren, MI, and have a place down in NC. It appears they manufacture their own products, but not verified that.
...just brainstorming, trying to solve a problem.