So, I ordered some T-Motor prop washers from HeliDirect and they arrived a couplel of days ago. They are slightly smaller in diameter than the Tarot washers, but I used one to secure a prop onto my Tarot motor - seemed to fit just fine. But I sent an email to HeliDirect, asking if these would be suitablel replacements and the response was no, they won't work. Here's a pic:
Personally, I don't see a problem, so I asked again. This time another person said that he didn't see why it wouldn't. So I'm going to test them out. When I complete the build, I will do a few stationary flights - simply hover over my front lawn and later inspect all props. I expect that they will work just fine.
Tarot support sucks. I've sent emails to Tarot directly as well as the U.S. rep. - no response from any of them.