In the last year I switched from all grain brewing with a cooler to all grain BIAB for the simplicity. I recently purchased a 15.5 gallon keggle from my LHBS. I usually make mid-range gravity ales, around 6% ABV. My question is, shooting for that level of ABV, does anyone know what the largest batch of beer I could make would be (assuming about 70% eff or so)? I used to make 5 gallon batches, but I would like to go a little bigger. I'm not sure that I would have the room to do a 10 gallon BIAB batch in the keggle... I do everything in the kettle, and start with full water volume. I do have 5 and 2.5 gallon kegs, so if I could at least get away with a large and small split batch around 7.5-8 gallons that would be cool too, any advice from someone with experience in this would be great, thanks.