I have a BKK-SIN flight on TG in business, (am star gold 2) connecting in SIN on a separate ticket to Hong Kong/SFO on SQ. Will TG interline the bag all the way for me, or will I have to go through immigration at SIN, collect it and clear immigration again after re-checking it with SQ?

It's a regulation carry on - but i might have some liquids. Maybe if they don't check it through I should try to carry it on. BKK is pretty good about allowing a heavyish but legal sized bag in business right?