I am on track for loosing about 750g -800g off mine and that is starting with a KH frame that is 500g lighter than a Nimbus 2!!! I have effectively replaced everything though 
I have a Monty Race and it comes in at 800g but I am having trouble liking it as although it bounces fine it is very round so tram lines and tracks strangely which isn’t worth 200g if I can’t ride it