How much burns mini bites should be fed?

Hi all, after alot of thought we are hopefully keeping the adult dogs on burns but changing the types [rice, maize and potato] periodically.

My puppy is on Wainwrights puppy at the moment but was hoping to put him onto burns mini bites, which iv heard really good things about!
I know you dont need to feed as much burns as other foods.
He is eating about 300-350g per day of wainwrights puppy but as an adult on burns he would only need about 200-250g per day.

Im not too sure how much burns mini bites he would need per day, so if someone could help me out I would really appriciate it.
Hes a very big bones Border Collie and his estimated adult weight is 20-25kg.

I havent got any mini bites yet as he needs to finish a large bag of wainwright, but I was just curious to work out how much he would need compared to wainwrights, and the cost difference.

Thanks in advance xx