Evaporated I think 66grams of propane is about 1cuft of gas. which doesn't seem to me to be that scary. A perfect air to fuel ratio would require mixing 16 cuft

Evaporated I think 66grams of propane is about 1cuft of gas. which doesn't seem to me to be that scary. A perfect air to fuel ratio would require mixing 16 cuft of air. And flammable range is narrow. Comparison, your kitchen is probably 1000 cuft. So I think you are right, slow leak isn't much of a hazard.