Yeah it would be easier to do half. But I have a 15 gallon mash tun, and my friend has a 10 gallon mash tun. We are trying to do it with 5 boils and the max he could put in for the grain bill with 1.25qts/lb. Otherwise we would have to do six boils.
So you suggest to measure the grain out separately for each tun and not mix?