New Thunderbird Day! I've had the IV for a while and just got the Vintage Pro today. Obviously I don't have any observations that haven't been made before, but it's interesting to see the differences - the longer, flatter headstock on the VP (although this photo exaggerates the difference a bit), narrower nut on the VP, belly cut on the VP, jack moved from top to side. And there are various little things, like the "shoulder" on the VP being more sloped than on the IV, and the body edges being slightly more rounded. Also note that the relative positions of pickguard, pickups, and knobs are slightly different. No question that the VP feels a little more alive and resonant too! I haven't weighed it, but I think it might actually weigh less than the IV.
The VP has flats on it, which is new for me, since I've been otherwise strictly a roundwound player. I thought I'd hate them, but they're not bad.
And the "Coffin Case" for basses fits it very well:
https://www.musiciansfriend.com/accessories/coffin-case-bass-guitar-coffin-case
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