Wow, wish you had posted this yesterday! Actually ordered one of those OKI-78SR-5/1.5-W36H-C from Mouser yesterday since they had a few in stock (shipping cost me more than the converter itself).
They were completely out of stock when I originally ordered all my other parts, so I had to order an OKI-78SR-5/1.5-W36-C. Had to de-solder the 90 degree header, and then solder a 3-pin straight header onto it. Still trust the correct part more than my homemade one though, so I'll just keep it for backup since I haven't built my HM yet.