You're welcome jakestolar, those little welders can do a lot of really good work, but they don't get a lot of penetration, especially as the base metals get thicker and cleanliness is critical in your weld prep. Pre & post flight everytime for a while and then at least once a week is a very good idea. While the metal you used looks fairly thick and shouldn't flex any, you still have reversing loads on those welds (push & pull) as the suspension works. Reversing loads are tricky as they promote fatigue failure (think of bending a paper clip back & forth). I'm not saying yours are going to fail, just trying to explain why you should keep an eye on them. If you see a really fine dark line or lines starting to appear running off from a corner, or a weld, or along the outside edge of a weld it could be a crack and should be checked out either using dye penetrant or magnetic particle examination.
What happens is water seeps into these really tight cracks and stays damp after the parts dry and dirt sticks to the dampness at the surface of the metal. A poor man's "mag" particle inspection might be to spray the welds with WD40 or some penetrating oil, wash them off & dry them then sprinkle talcum powder over them and blow it off. It should stick to the oil that stays trapped in any hairline cracks and give you a faint white hairline on the metal. Course this is not as good as a real dye pen or mag particle test and depending on whether you have any undercuts in your welds it could give you false positives too
Your plan to go with a billet aluminium piece is excellent, especially if you have a buddy who is a machinist or knows one who owes him a favour
If you are not in a hurry for it, I could draw you up a part in CAD suitable for a machinist to produce the piece. It would be a 2D machining drawing as all I have is a 2D CAD program. However it should be quite sufficient for a custom part like this. It might take me a couple of months as I would be doing it in my free time, of which I have very little at present, but it would be a fun project. All you would need to do is send me all the dimensions & measurements, such as ID of the clevis, OD of the lug, diameters of the holes, centre to centre distance of the bolt holes etc…
Happy Thanksgiving to all