I have started using it for .45 It is a pain in the ass to measure. I once heard someone say "It meters like corn chips". I would tend to agree, but the accuracy is pretty good and I still have 3lbs of it.
A 30a water heater at 220v only needs a 10-2 wire pulled for it. No need for a neutral. While 30a would be overkill for an oil fired water heater the ignitor will only draw what it draws as long as it is not underpowered.
Yes. No injuries are a good thing. One o the persons in the blind was a kid about 5-7. His father grabbed him one handed by the coveralls and took off like a bat out of hell. I am going to grab an extinguisher from work and leave it in there for the future.
Just a word of caution to hunters out there. Make sure if you are using a heater in your blind you have a FIRE EXINGUISHER on hand. We had a small incident this morning that could have burned the blind down or worse.