I mentioned the upper horn because the other bass I had, the NS fretless which I've sold, had a longer horn with a similar body shape to my euro.
Actually let me add some pics for a comparison.
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That basically fixes all the things with the euro to make it more comfy at least for a classical playing position, which is how I play.
No kidding but when talking about coziness the NS was more cozy than my euro. Still sold it cause I just didn't gel with it, but the shape for me works better.