I have only brewed one extract kit, and already kicking the AG option around. (I'm hooked) I saw that igloo has a max therm 5 gallon beverage cooler (approx. $40) that has an insulated lid and supposedly keeps ice for 5 days @ 90 F. Would this be worth a look at making a MLT? How big of a grain bill would this handle if kept to 5 gal batches? Or should I just go for the 10 gal to be on the safe side?