When many of the older designs were created, this was the most widely available gold metallic thread. Some craft stores, needlework shops, and online shops still carry it.
The newer designs tend to use Rainbow Gallery Petite Treasure Braids. These are much easier to use. The 284Z probably matches PB03 most closely although you may want to use PB01 or one of the other colors instead. Use two strands over two threads on 28 count or 32 count fabric or over one fabric square on 14 count or 16 count Aida. The Rainbow Gallery threads are available through needlework shops and online.
Another option is to use Kreinik braid in either the #4 or #8 size. #4 in thinner. The 002 and 002HL (high lustre is more sparkling) would be appropriate substitutes. Some of the others, 202HL and 221, would also work. You probably want to use two strands of #4 or one strand of #8. If you don't like the effect, try more or fewer strands.
