This dish is standard with us now...love it!! We use 30 gm green paste and that's just perfect for us. If we don't have chicken it makes a lovely vegetable curry.. Simply replace chicken with the same weight vegetables... I find root vegetables work best in place of the chicken. Carrots used to replace the bamboo shoots make for a nice sweetness,too.
To answer your question I can categorically say... Keep to the 600 gm.!! I tried 750 gm once and it simply does not work!!
If you need that quantity of curry I'd be making it in two batches.