I have been brewing 10 gallon AG batches for about 4 years. I started out AG brewing. Only experience I have with extract is making starters. My mash tun will hold about 34 lbs of grains, and that is the absolute maximum​. I am brewing a Pumpkin Pie Imperial Stout this Fall. It calls for 44lbs of grains plus pumpkin and a few other things, in the Mash. No way will I have enough room. There are 30lbs of 2-row. If I switch out, say 18lbs for extract, how do you do that? Thanks for any help!