I know you are not in favor of Eb Necks but playing my Hart mainly for the last few weeks as well as every other time I can see the advantage personally of the Eb over the D.
I looked over at my stand partner the other day at rehearsal and asked if his was D or Eb? He showed me as we discussed it and he has an Eb as well and does not like the D-necks. I have spoken to other players who feel the same.
With my thumb on the Heel my 1st finger plays D (on the G) and my 2nd plays the Eb. I can easily play a C on the E with the 1st and D with the 4th and the same across the Neck. On a D-neck I cant do that without a fairly uncomfortable stretch.
Now, on the 'copy' bass the shoulders will be sloped quite a bit more so maybe it wont be as important but I recall the original bass being more of an Eb as well. You can see here the difference in shoulders between the two.
Also, the distance from the top of the Heel to the root of the Neck in the block is much less making the transition into TP so much easier. Look here between the Hart and Martini to see what I am talking about.
Playing the Bass for just a few minutes testing it you will notice other 'feel' issues than the Heel depth but playing 2-3 hour long rehearsals and concerts is another story. I end up thinking about these details on the drive home almost every time.
For those of you with experience on both, which do you prefer? We talked about it awhile ago
here but the Thread has all but died out..