I received the following information from Antone Jones back in 2019 on the creation of Hoya Rebecca and Hoya Rachel:

This cross happened at my old nursery, Spring Valley Tropicals back in 2007 or 2008 (I can verify once I get home). The actual cross is Hoya lacunosa Langkawi Island (a smaller variety) x obscura. This one I did not do by hand (unlike Patricia and Naughty Noel) but I did witness and photo capture the moth/butterfly who pollinated it in action. The pod formed on the umbel not long after. Rebecca has a sister cultivar named, Rachel. They are from the same pod but the seedlings looked different to me and so I gave them each a separate name and tossed the rest of the seedlings away.

Antone Jones

This is kind of a cool feature of WordPress that I just discovered. Below is a slider that you can move back and forth; Hoya Rachel is on the left and Hoya Rebecca is on the Right. Move the slider to compare the two cultivars.