You don't have to chop it all off by any means. That was just my personal opinion 'cause I'm lazy, which is why I don't buy almost dead plants either. But if you do decide to cut, leave about 4 or so inches of stem from the soil surface. It'll backbud making each stem branch 2-4 branches. It wouldn't take that long to grow back (and it would) and it would be fuller and brighter. And those leaves that you cut really short, if they are adult leaves, chances are good that they'll be short for ever more. Now, if the plant seems pretty happy right now, you can just leave it as is, and keep a close eye on it. For all I know it could bounce right back. Some plants can have a crazy will to live. Whichever you choose, I wish you the best of luck with this plant. Perhaps your thumb is greener than anyone knows.

I am new to gardening myself and my basil was doing the same. I live in RI and watered every 2-3 days and it looked like I was leaving them in the sun to long but was told I was watering them to much. (Honestly I dk how people can tell.) What I did though and it has improved my plants a little is water every 2-3 days depending on the heat and I started putting them in areas where they had full sun for only 6-9 hrs a day. Once they bulked up a little I put them in brighter spots. This did not fix the problem completely but it did help a lot. Hope it helps you.

You are correct; it's sun damage. Some Hoyas can handle a western exposure and others can't. It's hard to predict because some of the species that can handle western light have much more delicate looking leaves than carnosa. I had my diversifolia growing in a west window all winter and it loved it, but in the spring I had to move it because it started to suffer. If you pull your blinds in the afternoon, as you've been doing, I don't think you will have any more problems. My leaves look exactly the same when they get too close to the grow lights.

Environmental -- sun; bright light; and/or brief water shortage.