I have successfully used Glenn's calls to call in a few hogs over the last several years. I haven't figured out any particular call or calling pattern but it does work sometimes. All of my calling has been done at night so I cannot speak for day calling results.
I can say when it works it's worth the effort. I have had a few come in hot across long distances in open fields and it gets your adrenaline up watching a hog headed straight for you from far off. I have also had some come in real close in the woods.
It seems they will try to come in downwind of the caller sometimes and if your caller is not very far out it gets interesting. I have had a couple of large hogs bust out of thick foliage at 15 yards or so and one was a large sow that was doing some vocalizing very close to me in some thick high grass. She was about 15 yards away and it was so thick I could not see her in my thermal and when she finally poked her head out I got a 6.8 round in her. Hearing her that close in the dark was one I won't forget.
If you are going to try calIing I recommend using the Glenn Guess calls since he has proven their viability in the field. They are available in the Convergent Hunting App and they also sell the Convergent Bullet caller which has worked well for me.
Convergent Hunting Solutions has developed the most innovative and natural sounding game calling equipment for hunting wild hogs and others.
convergenthunting.com