I have a very slow gas leak in my house that I simply can't find.

The gas is leaking at a rate of 1.7 cubic feet per day (0.071 cubic feet
per hour) as measured by the meter.

I don't smell gas anywhere, and I have looked at (sniffed actually)
every joint I could reach, and nothing.

My question is how sensitive of a detector would I need in order to find
this? I have seen detectors with ppm sensitivity ranging from 50 to
2000. Obviously price goes accordingly, how sensitive of a detector do I
need?

And realistically speaking, how bad of a leak is it? I know that any
leak at all sounds scary, but a leak so slow that you can't smell it is
not a fire hazard as far as I know, but it does waste gas.

-Ariel