Mingaun,
Some dealers are only helpful and friendly when you have a deal with him.
With pond of your size, not sure what type of jumbo koi your firendly dealer will recommend you. Not easy for 3 90cm fish to swim inside, not to mention growing them from tosai of 25cm.
And also for a beginner, investing in very expensive koi may not be fruitful, bec you will start to pickup your own appreciation taste and style along the way, and you would be selecting koi based on different attributes.
You have a established local Koi Club and forum which I believed you can get more direct assess and advice on koi keeping. And there are other dealers in KL for your to explore the relationship. (btw, I'm from S'pore and I frequent your friendly dealer too!)
pm me, if you have other private questions.
regards
PB.