One of the coolest designs, other than mine, was from an Austrian bbq site and the builder's craftsmanship was amazing. One thing incorporated in his was a reservoir mounted on a pole outside and control via hand valve. When the fill tube went through side of barrel, there was a sightglass for seeing the pan's fluid level! The brackets and attention to decal rivaled some of my friends that do indycar/aircraft fabrication work. Lots of hand hammered brackets and rivets. Beyond beautiful. On my smokers I size the pan to service in around two hour intervals. Then it takes only seconds, plus it's usually time to wrap, glaze or pull something at those times. Outside reservoirs can be problematic due to tempertaure of the fluid being added. That's why if I want to cool things down, put cooler fluid in pan and so on.Hotter fluid being added will take less time to get back to cooking temps. Steve.