Regards to the nozzle I've had a response from G&G (see post previous to yours) and they've confirmed that it's 21.1 mm which puts it into "probably an M4" range. I'm going to give one of the Lonex air seal ones a try and if that doesn't work I'll just splash out on a proper G&G one.
As for Taiwan....well, it depends on who you ask. Yes, Taiwan is a sovereign state with its own government (Republic of China) but Taiwan says that the Peoples Republic of China is theirs and that the communist government is having a bit of a laugh, Beijing on the other hand says they own Taiwan (they claim it's their 23rd province) and that THEY have dominion over all of China. The nub of it is that they no longer have membership of the UN and indeed are not recognised by the UN and are widely unrecognised by other countries. There's still nations that maintain diplomatic relationships with the ROC but not everyone. They're kind of the Far East version of Scotland really.