Maybe these shots of my old 6 lug student model shell with a ruler against it can help.. if the shots don't work for you here's what it looks like to me..

One picture is with the ruler against the batter head measuring toward the bottom of the drum.

The other is with the bottom of the drum on a flat surface measuring toward the top of the drum.

1 9/16" from a flat surface to the bottom hole.

4 1/8" from a flat surface to the top hole.

That's my best amature effort..

This drum is a looped S badge 59-60 with the rapid strainer.

Maybe these measurements weren't even your question..?

All the best..

Yes they were Jim. You are a gentleman and a scholar. Thanks very much for taking the time to prepare and post these images.

I really appreciate it and all the best to you too.