Going be doing a Russian Imperial Stout in the near future and was wondering what max brew length I could get out my Coleman Xtreme 66L cooler? A 34L batch needs 16kg of grain and a mash volume of 40 litres for example Going to be using batch sparging method. The top up is -3 litres for batch #1 and 20 litre for batch # 2. Do you think I can increase the brew length? Should I drop efficiency to about 60% compared to my usual 75%. Might even bottle it in 330ml bottles as 500ml is probably too much :)