Glass Plate Film Holders and Film Plane

I have a couple of 5X7 glass-plate holders that have the film-holder inserts in them. The wooden holders themselves are much thicker than more modern film holders. I'm wondering if there is anything to worry about as far as the film plane goes in relation to the screen image as compared to more modern holders.:confused:

Of course, I realize, testing is probably the only answer.

All holders vary -- even among the same brand. I like the rig someone showed me -- basically a popcicle stick with a toothpick rubberbanded to it. Take off the back, span across the back with the stick and push the toothpick down until it touches the GG. Now put a film holder (w/o darkslide but w/ old piece of film) in the back and measure again, judging by how close the tip of the toothpick is to the emulsion of the film. The closer the better, of course.

Vaughn