Oh my! Look at this

[incubus2432]

I'm not too sensitive to neck dimensions and I've been refereed to as a giant gork so take my opinion lightly.

I find the 4004 necks very comfortable to play and don't agree with them being classified as chunky. Some 4001/4003 and a few jazz bass necks have felt a little too thin to me. It's all relative to what you prefer and how sensitive you are to the differences.