A little but important update. Great news, both pickups are in working order, the test with the stereo headphones was a succes! And it's definitely a short scale instrument, the tape measure can't be wrong!
And John, your advice about the trim pots on the back proved very useful, and yes indeed, all the tweaking resulted in full - centered - centered - full for me also!
I'm very thankful to be part of this great group of people, the support and interest is absolutely mindblowing...