Update - I arrived BKK a few days ago, from HKG (I’m an Australian citizen, so visa exempt). At the Immigration desk, I handed over my APEC card, and received a 90 day stamp in my passport.
I arrived in BKK tonight, and can now confirm there are two forms to complete, the T8 form and a health declaration (plus the normal arrival card). Thanks again folks.
Agoda’s SHA+ search includes a bunch of hotels offering the five day two test option you’re looking for (you need to search for five nights for this option to pop up). Also, if you go to the individual hotels’ websites, some of them specifically mention this five day option. Good luck.
I am also interested. I would normally get 30 days when I arrive (Aussie, so no visa required), however I plan to present my APEC card to see if the Immigration Officer gives me 60 days (🤞).