I’m flying SQ out of Seattle in 2 weeks. Seattle to Singapore to Bangkok on one ticket, arriving at BKK at 8:35 AM. 5 hours later, I fly BKK to CNX on Thai airways. Both economy but Thai allows 20 kilos and SQ allows 2 bags at 23 kilos apiece. Is it hit or miss at Seattle, checking bags through to Chiangmai? From what I’ve read, I won’t even try to get Thai airways to book bags through to Seattle on the return.