I have a single RG4. Mine is a 313640. I finallyot good bullets when I went to the ladle. It wasn't a fault of the mould, I just did get it got enough and keep it there. Not much lead between the nose and HP pins, gotta get the mould and pins really hot for decent fillout.
I have 3 of the MP Cramer type HP moulds. They cast very well. My biggest issue with them is getting them too hot and casting too fast. The nose breaks when the pins pull the bullet from the cavity. This is because the bullet isn't hard enough when I open the mould.
Moral of the story, they both work. Each requires a bit of learning and understanding. I prefer the MP moulds on the whole but if NOE had an HP I really wanted I would get another one.