A fettle with good fitting tools when things go as they should is one thing...
A fix when they don't - mainly truss rod - is another...
Well done for sorting yours and ya mates basses... as you say bit of research and the correct tools and an appreciation of how things should react... engineering background, sorted!
Maybe get a cheapy or an old broken neck of the bay and try fret leveling how it feels etc, nut file etc.