It is always a stretch to squeeze 10 gallons out of my normal setup, but this was the first attempt at a double mash IPA. My 10g mash tun can hold about 24# grain + water, but this IPA required much more. I estimated the water volumes, but ended up having more than the 15g kettle could accommodate. I just boiled it down until it could hold the chiller and began the 15 minute countdown. Even then, I had about 2g extra wort and will recalibrate the next time I go with this technique again.
I upgraded my chiller mid-batch and it is so far superior to my original one.
1.058 with split yeast
American Ale
London III
66 degree ferment; gassing off steadily now.