I always use the same or perfectly matched spotmeters for everything. TTL metering introduces certain extraneous variables, though what is most important is to simply be well accustomed to your specific chosen method. And gray cards? Ha! I've experimentally gone thru stacks of them and measured
the full visible spectral response on a continuous tone spectrophotometer. Not only were none of them actually 18% gray, but they varied widely with regard to the point on the spectrum where they even approached it. Even cards from the same manufacturer varied significantly - enough to spoil a critical chrome exposure, for example. An unfaded Macbeath Color Checker chart with both color and gray patches is a much better option, with respect to quality control. When we calibrate spectrophotometers, it's always with a special ceramic tile, which won't fade or absorb stains. My color vision is highly trained, and I've gotten good enough at estimating outdoor exposures from sheer experience in analogous situations that on a couple of mtn trips when I accidentally dunked my meter in icy streams, even my 4x5 chromes came out perfectly exposed. But that formula probably wouldn't work very well in unfamiliar circumstances. It's really a function of memory, from thousands of analogous shots, and not of any innate physiological ability to properly judge luminance value. So with regard to the original question - I'd give a strong "NO". Use a light meter for anything critical. And leave that "film latitude" excuse
to Aunt Maude with Kodak Gold in her Holga.