Not too long ago in a FB group, don’t remember which one a guy set up his own gears, posted a picture of the mesh asking how he did. Now I’ve looked in shop manual and seeing what gear mesh should look like and they looked good to me. But that doesn’t mean anything. Of course there had to be a big discussion on it. Quite a few people who actually did this type of work chimed in. I don’t recall all the details but what can cause whine is the type of use the gears will be used in. A couple said for drag racing I think the backlash was set tighter and I think would cause noise. Maybe look into this? Find a shop that does more race type of work and see what they say.