Hello!
“Draftboard” refers specifically to the “Proofgrade” brand MDF sold by Glowforge. If I remember correctly, it comes in ~1/8" (“Medium”) and ~1/4" (“Thick”). The “Thick Draftboard” settings in the UI refer to the later.
What you bought on Etsy is likely something entirely different.
The best way to figure out the settings is to do some testing. Here is a write-up on how:
Since Glowforge support staff won’t be able to help with non-Proofgrade materials, this probably needs to get moved to Beyond the Manual to get additional community help.