Mashed with 19.2 quarts to hit 151. Added 1 gallon @ 121, sparged. Added 3.25 gallons of boiling water to bring to about 170, drained to collect 6.5 gallons.
Brought to a boil outside and promptly ran out of propane. Brought inside and put on stove. Was unable to get a good boil going which resulted in less boil-off than expected.
Collected around 6 gallons of wort. This measured and cooled. The SG was 1.074. Assuming I actually collected 6 gallons (there was foam, I couldn't tell) I would have hit my predicted gravity of 1.088. I seem to have fixed my efficiency problem by crushing way more than I used to. This batch was at least twice as fine as I normally crush.
Fermenting in a bucket in the closet. Ambient temperature in the apartment hovers around 62.