The original pressing of the artists you are looking for are quite expensives.
More often than not, the original pressings sound much better.
The post 1992 album of these singers are either not avail in lp format or are later issues (release much later than the original cd). Usually for these albums, the first press cd sound better.
However there are some steller sounding records of these taiwanese or Hong kong Singers in 1990 1991. This is a period which Hk has already stopped or has very limited production. The production was moved to South Korea using the master tapes/dat