FWIW, I spent 18 years in propane and natural gas.Hank Hill ain't got shit on me. For "mileage" comparisons,LP has 93,180 btu's per gallon. Weight is 4.24 lbs/gallon.Grill cylinders are filled to 80% liquid capacity,resulting in about 4.7 gallons per tank. Blue Rhino stops at 4.5 for "safety margins",and it also doesn't hurt "profit margins".
That heater you're looking at should work well for your needs. Stay clear of anything running on Coleman campstove cylinders.$$$
I've had one of these,
,for my shop forever.It's a little slower than what you're looking at,but has 3 settings(1,2,3 burners),and during a power outage(or campout) you can remove it from the cylinder collar,lay it on it's back and make Mac&Cheese.
Back in '03,Isabel knocked my power out for 5 1/2 days.I lol'd.
EDIT;I feel I should have a disclaimer here,but the heater I have is 99% efficient.The reason it's outdoor rated is because the cylinder itself is not approved for indoor use.
Years ago,a customer had this cool little rollaround infrared cabinet heater with a 20# cylinder in the back.By the time I went looking for one they had been jerked off the shelves because of the cylinder.