I suggest running a test to establish your personal ISO for the film/camera you are using. Briefly, cap the lens and click off three frames, take an 18% gray card and in a constant light and at box speed take a meter reading, without really focusing cover the frame with the gray card and no background. Then take exposures starting at +2 stops, +1 1/2, +1,+1/2, as metered, -1/2, -1, -1 1/2, -2. You will now have finished a roll of 12exp's. Develop as per mfg's time and temp for that film. After the film has been processed and dried take one of the unexposed frames and make a test print at an 8x10 enlarger height with your #2 filter if using MG. After the print has been processed washed and dry see at what time you can see a change from black. Then cut nine pieces of unexposed printing paper and mark the on the other side with a pencil to match the exposures for the other negatives. Expose each one for the time you found for the change from black. Process all the same and when dry see which one is closest to the neutral gray. Adjust your ISO accordingly. Shoot another roll of whatever you wish using that ISO and process as usual. You should be able to make a decent print with the #2 filter. You can then tweak as needed for contrast either with filters when printing or when developing the film.

IMO it's best to standardize for each film/developer/paper/etc combo. Then when you want a particular effect or look you have a minimum of variables.