I think it's better not to guess the amount of sales of CG. No one knows the real amount and the ordinary sales people will never tell us the truth. Maybe they don't even know!
There's a lot of talk and rumours. Some say 80% sales, some say 60%, some say less than half, the more pessimistic ones say it's a complete flop, etc. All those figures are "heard by someone" but there is no official verification. When you combine a 3rd world country like Malaysia with "anything also can" China, it's really anything goes! There is no proper and strict system like Singapore where you can easily check the facts and figures.
There is also another rumour that says many China Chinese were the first buyers. They got it as a "buy 1 get 1 free" offer by the developer. But this rumour has not been verified though I won't be surprised if it's true. CG doesn't mean much to them. Why would they want to live there and work in Malaysia? If these Chinese really bought units there, some say it's to "wash dirty money" if you know what I mean. Most likely, they are simply flipping them to get the cash and say goodbye.
Many of the sellers who flipped CG by selling RM30-50k more than the early bird prices were from China. They were the ones whom the developer first released the units to. Unfortunately, many from Singapore didn't do sufficient homework and mistook it for a good opportunity. They picked up the crumbs thrown away by the China buyers and were sucked into paying the extra costs.
The number of units in CG is just too massive. It's unthinkable. Whether it's for own stay or investment, it's just out of the world but not in a good sense. Almost always, those who are against Iskandar properties will cite CG as the "notorious" development that will fail badly in terms of being a ghost town, little value, no rental, no buyer, poor workmanship and ultimately left to "decay" through time that is typical of some JB condos.