[Ken Smith]

Originally Posted by Pino Cazzaniga

This is amusing, somehow.
Here the current preference is the one you said, Ken, the thumb at the heel, the second finger opposite, the first finger plays D on the first string.
The trend is for a little stretch of the first finger toward the nut to reach D.
And we name it D neck.
There are many long neck grafts, made until the '60, where in the same position, thumb at the heel, second finger opposite, the first finger plays Eb. We name these Eb necks.
I don't know why they made these long neck grafts, probably they wanted to reach more notes with the hand at the heel in orchestra playing, and a longer string lenght for the gut strings they used these days.
Anyways, the D neck as we call it here, or the "proper" D neck you said, allow us some freedom to find a better balance for middle positions, where some variables are neck height over the top, body outline near the neck, string lenght, bridge height, stop lenght and so on.
It's over the standard, a good reason to play and work on basses, I hope.

So, across the Ocean or rather Ocean'S, my idea of the 'Original' 'D-Neck' verses the 'Modern' 'D-Neck' can be easily explained;
Original D = Modern Eb.
Modern Eb = Original E.
Modern D = Original Db.

I can't tell you what a struggle it is going over the shoulders to the F# or G when climbing up the Neck of a modern D vs. an Original D or modern Eb. I sop much prefer the Eb at the heel for the lower positions to Thumb positions. Takes a half step out and some physical mass as well.