My suggestion and take it how you will.
eBay has a good deal on a Unibear 520 O ring chain about $35 shipped (these cost $25 in china and it’s over 2kg so cant ship or match the price)
I’ve had local chain n sprockets sets fail n break in 428 and looking at your USA costs for say a fair DID O ring you are at or more expensive then a decent unibear chain and that’s plenty strong enough on air cooled Chinese bikes.
I had a customer in China fit 1 and that lasted very long and I’ve had 428 break.
My suggestion is 520 unibear o ring chain and sprockets even with say a cheap chain breaker and chain cleaning brush from china you’ll not be up for much more then say a DID 428 chain.
USA has sprocket options n China has a bit more maybe not as good quality but good enough to replace as a set etc
I believe this is the better bang for buck way to go and that’s what I do in China on air cooled motors.
https://rover.ebay.com/rover/0/0/0?m...2F222121202245
Think 110 or couple extra links is fine and cheap chain breaker sorts the length out easily enough.
My RX3 has like a unibear chain but that’s not good enough so I buy an imported chain for that to avoid it stretching but the NC300 is another animal.