First of all, you haven't calibrated anything to anything.(posted 8500 days ago)It's pretty well-known that light meter manufacturers don't agree on a standard and there is no real standard...so you have to come up with your own.
The 18% grey card is a pretty handy and relatively standard reflection target; the Wallace Expo-Disc is a handy 18% transmission target.
Assuming you're not living in the far north or the tropics, "Sunny f16" should be valid. That is, when metering a grey card or Expo-Disc in full direct sunshine the light meter should read 1/EI @f16. Arbitrarily pick an EI, say 125, and set that on the meter, set the lens at f16, read the target and the recommended shutter speed should be the same as the EI, in this case, 1/125.
If it is, you're done. If not, adjust the meter's EI setting until it reads 1/125 @f16. How many thirds of a stop you have to set the meter EI to get that reading from what it should be will be the correction factor for that meter.
For example, if you have to set the meter EI at 80 to get 1/125 @f16, what you've learned is that you need to set the meter EI 2/3 stop lower for _all_ EIs with that meter.
Chances are you'll have different correction factors for each meter.
Once you've gotten that squared away, you can proceed.
The traditional minimum Zone I density is .10 DU above fb&f. This isn't engraved in stone; if you find that you want more or less shadow detail adjust that target accordingly.
Now you're ready to test. Light bulbs put out lots of IR and meters are sensitive to IR out of proportion to the visible light the bulbs put out, so do this outdoors. Set up so that the meter sees only the target (grey card or Expo-Disc) and set the aperture to f2.8, then set the shutter speed to whatever's indicated. Stop down three stops, which would be the anticipated Zone II, and shoot a series of exposures while stopping down two stops. Ideal would be decreasing exposures in 1/3 stop intervals but that's just about impossible to do if your camera doesn't have click-stops in 1/3 stop intervals. The reason for starting out at f2.8 is so that the shutter speed will be high enough that reciprocity failure isn't a factor.
Develop the negs and read 'em with the densitometer. With luck your Zone I exposure will be .10 DU above fb&f. If not, if for example you don't see .10 DU until Zone II, then you know that with your equipment your working EI for the film is a stop lower than whatever you used for the test.
For TX developed in "normal" developers I'd expect to see EI 200 to EI 400; too far off from that range would send me looking for an error.