B/W film use - green yellow filter or just the yellow filter?

My interest was more in streamlining complex lab processes, since I have never done such manipulations digitally, nor intend to, but only by old
fashioned punch and register comp techniques. Sometimes a particular filter will split the difference and allow the use of one sheet of film instead of
two for a certain preliminary masks. Outdoors, I keep things real simple, just a few high quality coated glass versatile filters such as a 25 red and
some version of orange, either light or dark, depending. No need for a 11 with ACROS film (or in my case, an equivalent Hoya XO light yellow-green),
but I'll carry one for TMax films or Pan F. For dayhikes with the 8x10 I'll be more targeted in the day's results, and might carry a deep green or even
a 47 blue. I often admire the graphic effect, open shadows, and exagerratated atmospheric effects of 19th C blue-sensitive plates. There is no right
or wrong involved, just intelligent creative choices. I'm sure you passed that truth on to your students too!

Light yellow (1.5x) for the Spring, orange for cityscapes, medium or dark yellow for Summer; experiment in the Fall. I also like a b12 blue for storefronts in shadows.

The best answer to this question is, like most things in life, "it depends". On the film(s) you are using.

Last year I bought a beaut early 1950s Voigtlander Perkeo I with the Color Skopar lens (apparently an oddity, as the I's came with Vaskars, never mind) which came with a few original Voigtlander filters. I keep the UV on the lens for color work, but have found the yellow green (YG) to be ideal for most B&W images using "traditional" 120 film - in my case, Ilford HP5 and FP4. I haven't tested with Ilford Delta films, but I occasionally use these in my Nikkormat, and find the yellow (not YG) filter works best. Horses for courses.

Not surprisingly, the YG produces yucky results on Ilford XP2, as it would on all C41 color emulsions. I use a lot of 120 XP2 for architectural work, and have found the only filter that produces acceptable results for me is a light yellow, to bring out clouds and tones in stone facades. Orange seems to have no useful effect on XP2.

I am not really a big user of orange filters as I seldom shoot landscapes with rocks or stones, and in 50+ years of looking at the world through my various cameras I have yet to use a red filter. Others on this site will probably tell you more about these filters.

The usual tests will show you if the results suit you or not. This is the best way to go.

If I use a filter at all then all I use is deep red or maybe a light yellow for ortho type films such as Rollei Ortho25 and Adox CMS20.
Super panchromatic films like Rollei Retro 80s will give an IR effect with a deep red due to there increased red sensitivity.
Films I mainly use are Rollei Retro 80s, RPX 25, Ortho 25, Kodak Tmax400 or 100 and Adox CMS20II

All of these films also perform very well without any filter at all and that is how I prefer to use them my self

Tri-x + Y2 yelow and I am happy!

I like yellow-green. In my area, the Southwest, it seems to resonate with the landscape. Certainly has more character than basic yellow.