I bought black anodized aluminum rims for my RD350 this winter from "lgarage" from Thailand. Likely the same source. I did not want to use the heavy "H" style rims from MikesXS. The ones listed were 1.6"f and 1.85"r width but I messaged him and got 1.85"f and 2.15"r width for a couple bucks more. I was impressed with the quality, look very nice, a bit of distortion near the weld but nothing major. I bought stainless spokes/nipples from Buchannons for a bit over $200. So I was all in a bit over $400, laced and trued myself. I was able to get them true within a few thousandths of an inch.
https://www.ebay.com/itm/264092013892?fits=Model%3ARD350&hash=item3d7d1c5544:g:eAsAAOSwvWFfklH2
https://www.ebay.com/itm/264092013892?fits=Model%3ARD350&hash=item3d7d1c5544:g:eAsAAOSwvWFfklH2