If the chamber on your Ackley is cut properly (crush fit) with factory or properly sized brass, head space will not be an issue. I use the same load for fire forming as I do in the already fire formed brass. IMHO the cream of wheat method is one of the stupidest things I have ever heard of.

"Before you criticize someone, walk a mile in their shoes. That way, you'll be a mile from them, and you'll have their shoes."